Anemia in the pediatric patient



chromosome deficiency syndrome :: Article Creator

Uncovering Late-onset Combined Immune Deficiency In Chromosome 18q ...

Chromosome 18q deletion (18q del) syndromeis a rare genetic condition disorder, affecting approximately 1 in 40,000 to 55,000 individuals, caused by the deletion of genetic material on the long arm of chromosome 18. This genetic anomaly disrupts normal growth and development, and critically, can impair the immune system's functionality. Patients with 18q del syndrome often exhibit humoral immunodeficiency or a common variable immunodeficiency (CVID)-like phenotype, characterized by low levels of immunoglobulins (antibodies) in the blood, compromising the body's ability to effectively combat infections.

Now, however, in a study published recently in the Journal of Clinical Immunology, researchers from Tokyo Medical and Dental University (TMDU) and Kagoshima University have identified a previously undocumented manifestation among patients with 18q del syndrome: late-onset combined immunodeficiency (LOCID), affecting both B and T cells. This novel finding underscores the critical importance of routinely assessing the functionality of both B and T cells in individuals with 18q del syndrome.

Elaborating further on this novel finding, Professor Kanegane says, "In this study, we came across two patients with chromosome 18q del syndrome presenting with LOCID, which, to the best of our knowledge, has not yet been reported in patients with the syndrome."

Patient 1 was a 29-year-old man diagnosed with 18q del syndrome. Despite initially having few infections, he developed Pneumocystis pneumonia (PCP). Array-based comparative genomic hybridization (CGH) analysis showed a deletion in the 18q21.32-q22.3 chromosome region.

Patient 2 was a 48-year-old woman who had not been previously diagnosed with 18q del syndrome. However, she was diagnosed with granulomatous lymphadenitis, and a biopsy of her lymph nodes revealed a loss of 18q21.33-qter.

Both patients exhibited hypogammaglobulinemia, characterized by abnormally low levels of immunoglobulins (IgG, IgA, IgM, and IgE). Patient 1's serum immunoglobulin levels were significantly below normal ranges. He reported IgG of 188 mg/dL (normal: 870-1,700 mg/dL), IgA of 105 mg/dL (normal: 110-410 mg/dL), IgM of 26 mg/dL (normal: 33-190 mg/dL), and IgE of <5 IU/mL (normal: 232 IU/mL). His CD4+ T cells had a decreased percentage of naïve T cells, accounting for only 3.58% of the total CD3+CD4+ cell population. Moreover, his T-cell receptor excision circles (TREC) levels and Ig κ-deleting recombination excision circle (KREC) levels were extremely low at 25.27 copies/105 cells (normal: > 565 copies/105 cells) and 93.36 copies/105 cells (normal: ≥ 456 copies/105 cells) respectively, indicating poor T-cell production.

Similar conditions were noted for patient 2, who reported IgG of 8 mg/dL, IgA of 9 mg/dL, IgM of 131 mg/dL, and IgE of 0.3 IU/mL. Her CD4+ T cells and naïve CD4+ T cells were depleted, with naïve T cells accounting for only 6% of the CD3+CD4+ cell population. Her TREC levels were 0 copies/105 cells, and her KREC levels were 11.4 copies/105 cells.

Importantly, CD4+ and CD8+ T cells failed to divide in response to phytohemagglutinin (PHA) stimulation, indicating severe functional impairment of T cells in both the patients.

Based on their immune profiles and clinical history, both of them were diagnosed with LOCID, a condition where both humoral (antibody-mediated) and cell-mediated immune responses were impaired, making them highly susceptible to infections.

This novel finding is significant, as Dr. Tomomasa, the co-authored of this study, states, "While cases involving deletion of the same region as those of the two patients presented in this study have been reported earlier, patients with 18q del syndrome developing LOCID have never been reported. We speculate that these patients simply have not yet developed LOCID or that they might not have been adequately assessed for it."

On the basis of these results, the researchers recommend annual testing for both cellular and humoral immunity in patients with 18q del syndrome. This proactive approach can allow for the early detection of combined immune deficiencies, facilitating timely interventions and personalized treatment strategies. Ultimately, such regular monitoring can significantly improve clinical outcomes and enhance the quality of life for individuals diagnosed with 18q del syndrome.


Chromosome 21 And Down Syndrome: From Genomics To ... - Nature

Hsu, L. Y. In Genetic Disorders and the Fetus (ed. Milunsky, A.) 179–248 (Johns Hopkins Univ. Press, Baltimore, 1998).

Google Scholar 

Bailey, J. A. Et al. Recent segmental duplications in the human genome. Science 297, 1003–1007 (2002).

Article  CAS  PubMed  Google Scholar 

Pentao, L., Wise, C. A., Chinault, A. C., Patel, P. I. & Lupski, J. R. Charcot–Marie–Tooth type 1A duplication appears to arise from recombination at repeat sequences flanking the 1.5 Mb monomer unit. Nature Genet. 2, 292–300 (1992).

CAS  PubMed  Google Scholar 

de Mollerat, X. J. Et al. A genomic rearrangement resulting in a tandem duplication is associated with split hand-split foot malformation 3 (SHFM3) at 10q24. Hum. Mol. Genet. 12, 1959–1971 (2003).

CAS  PubMed  Google Scholar 

Snijders, A. M. Et al. Assembly of microarrays for genome-wide measurement of DNA copy number. Nature Genet. 29, 263–264 (2001).

CAS  PubMed  Google Scholar 

Ellis, D. & Malcolm, S. Proteolipid protein gene dosage effect in Pelizaeus–Merzbacher disease. Nature Genet. 6, 333–4 (1994).

CAS  PubMed  Google Scholar 

Inoue, K. & Lupski, J. R. Molecular mechanisms for genomic disorders. Annu. Rev. Genomics Hum. Genet. 3, 199–242 (2002).

CAS  PubMed  Google Scholar 

Readhead, C., Schneider, A., Griffiths, I. & Nave, K. A. Premature arrest of myelin formation in transgenic mice with increased proteolipid protein gene dosage. Neuron 12, 583–595 (1994).

CAS  PubMed  Google Scholar 

Magyar, J. P. Et al. Impaired differentiation of Schwann cells in transgenic mice with increased PMP22 gene dosage. J. Neurosci. 16, 5351–5360 (1996).

CAS  PubMed  PubMed Central  Google Scholar 

Lettice, L. A. Et al. A long-range Shh enhancer regulates expression in the developing limb and fin and is associated with preaxial polydactyly. Hum. Mol. Genet. 12, 1725–1735 (2003).

CAS  PubMed  Google Scholar 

Albertson, D. G., Collins, C., McCormick, F. & Gray, J. W. Chromosome aberrations in solid tumors. Nature Genet. 34, 369–376 (2003).

CAS  PubMed  Google Scholar 

Hassold, T. & Hunt, P. To err (meiotically) is human: the genesis of human aneuploidy. Nature Rev. Genet. 2, 280–291 (2001).

CAS  PubMed  Google Scholar 

Antonarakis, S. E. 10 years of genomics, chromosome 21, and Down syndrome. Genomics 51, 1–16 (1998).

CAS  PubMed  Google Scholar 

Bandyopadhyay, R. Et al. Parental origin and timing of de novo Robertsonian translocation formation. Am. J. Hum. Genet. 71, 1456–1462 (2002).

CAS  PubMed  PubMed Central  Google Scholar 

Epstein, C. J. In The Metabolic and Molecular Bases of Inherited Diseases (eds Scriver, C. R., Beaudet, A. L., Sly, W. S. & Valle, D.) 1223–1256 (McGraw-Hill, New York, 2001).

Google Scholar 

Roizen, N. J. & Patterson, D. Down's syndrome. Lancet 361, 1281–1289 (2003).

PubMed  Google Scholar 

Pennington, B. F., Moon, J., Edgin, J., Stedron, J. & Nadel, L. The neuropsychology of Down syndrome: evidence for hippocampal dysfunction. Child Dev. 74, 75–93 (2003).

PubMed  Google Scholar 

Hattori, M. Et al. The DNA sequence of human chromosome 21. Nature 405, 311–319 (2000). Landmark study that reports the high-quality nearly-complete nucleotide sequence of HSA21. Important for molecular studies on HSA21.

CAS  PubMed  Google Scholar 

Lander, E. S. Et al. Initial sequencing and analysis of the human genome. Nature 409, 860–921 (2001).

CAS  PubMed  Google Scholar 

Venter, J. C. Et al. The sequence of the human genome. Science 291, 1304–1351 (2001).

CAS  PubMed  Google Scholar 

Reymond, A. Et al. From PREDs and open reading frames to cDNA isolation: revisiting the human chromosome 21 transcription map. Genomics 78, 46–54 (2001).

CAS  PubMed  Google Scholar 

Reymond, A. Et al. Nineteen additional unpredicted transcripts from human chromosome 21. Genomics 79, 824–832 (2002).

CAS  PubMed  Google Scholar 

Davisson, M. Et al. Evolutionary breakpoints on human chromosome 21. 78, 99–106 (2001).

Gardiner, K. & Davisson, M. The sequence of human chromosome 21 and implications for research into Down syndrome. Genome Biol. 1, 1–9 (2000).

Google Scholar 

Gardiner, K., Fortna, A., Bechtel, L. & Davisson, M. T. Mouse models of Down syndrome: how useful can they be? Comparison of the gene content of human chromosome 21 with orthologous mouse genomic regions. Gene 318, 137–147 (2003).

CAS  PubMed  Google Scholar 

Pletcher, M. T., Wiltshire, T., Cabin, D. E., Villanueva, M. & Reeves, R. H. Use of comparative physical and sequence mapping to annotate mouse chromosome 16 and human chromosome 21. Genomics 74, 45–54 (2001).

CAS  PubMed  Google Scholar 

Rogers, M. A. Et al. Hair keratin associated proteins: characterization of a second high sulfur KAP gene domain on human chromosome 21. J. Invest. Dermatol. 122, 147–158 (2004).

CAS  PubMed  Google Scholar 

Shibuya, K. Et al. A cluster of 21 keratin-associated protein genes within introns of another gene on human chromosome 21q22. 3. Genomics 83, 679–693 (2004).

CAS  PubMed  Google Scholar 

Mural, R. J. Et al. A comparison of whole-genome shotgun-derived mouse chromosome 16 and the human genome. Science 296, 1661–1671 (2002).

CAS  PubMed  Google Scholar 

Watanabe, H. Et al. DNA sequence and comparative analysis of chimpanzee chromosome 22. Nature 429, 382–388 (2004).

CAS  PubMed  Google Scholar 

Kapranov, P. Et al. Large-scale transcriptional activity in chromosomes 21 and 22. Science 296, 916–919 (2002). DNA chip technology used to study the transcriptional potential of the genome.

CAS  PubMed  Google Scholar 

Kampa, D. Et al. Novel RNAs identified from an in-depth analysis of the transcriptome of human chromosomes 21 and 22. Genome Res. 14, 331–342 (2004).

CAS  PubMed  PubMed Central  Google Scholar 

Cawley, S. Et al. Unbiased mapping of transcription factor binding sites along human chromosomes 21 and 22 points to widespread regulation of noncoding RNAs. Cell 116, 499–509 (2004). DNA chip technology used to identify functional elements of the genome.

CAS  PubMed  Google Scholar 

Waterston, R. H. Et al. Initial sequencing and comparative analysis of the mouse genome. Nature 420, 520–562 (2002). The sequence of the mouse genome provided the opportunity for comparative analysis to identify human functional genomic elements.

CAS  PubMed  Google Scholar 

Dermitzakis, E. T. Et al. Numerous potentially functional but non-genic conserved sequences on human chromosome 21. Nature 420, 578–582 (2002).

CAS  PubMed  Google Scholar 

Dermitzakis, E. T. Et al. Comparison of human chromosome 21 conserved nongenic sequences (CNGs) with the mouse and dog genomes shows that their selective constraint is independent of their genic environment. Genome Res. 14, 852–859 (2004).

CAS  PubMed  PubMed Central  Google Scholar 

Dermitzakis, E. T. Et al. Evolutionary discrimination of mammalian conserved non-genic sequences (CNGs). Science 302, 1033–1035 (2003).

CAS  PubMed  Google Scholar 

Kirkness, E. F. Et al. The dog genome: survey sequencing and comparative analysis. Science 301, 1898–1903 (2003).

PubMed  Google Scholar 

Frazer, K. A. Et al. Noncoding sequences conserved in a limited number of mammals in the SIM2 interval are frequently functional. Genome Res. 14, 367–372 (2004).

CAS  PubMed  PubMed Central  Google Scholar 

Thomas, J. W. Et al. Comparative analyses of multi-species sequences from targeted genomic regions. Nature 424, 788–793 (2003).

CAS  PubMed  Google Scholar 

Patil, N. Et al. Blocks of limited haplotype diversity revealed by high-resolution scanning of human chromosome 21. Science 294, 1719–1723 (2001). A whole chromosome linkage disequilibrium mapping that provides tools for association studies of human complex phenotypes.

CAS  PubMed  Google Scholar 

Davisson, M. T. Et al. Segmental trisomy as a mouse model for Down syndrome. Prog. Clin. Biol. Res. 384, 117–133 (1993).

CAS  PubMed  Google Scholar 

Kahlem, P. Et al. Transcript level alterations reflect gene dosage effects across multiple tissues in a mouse model of down syndrome. Genome Res. 14, 1258–1267 (2004).

CAS  PubMed  PubMed Central  Google Scholar 

Reeves, R. H. Et al. A mouse model for Down syndrome exhibits learning and behavioural deficits. Nature Genet. 11, 177–184 (1995). First phenotypic analysis of the most-used mouse model with partial trisomy 16.

CAS  PubMed  Google Scholar 

Baxter, L. L., Moran, T. H., Richtsmeier, J. T., Troncoso, J. & Reeves, R. H. Discovery and genetic localization of Down syndrome cerebellar phenotypes using the Ts65Dn mouse. Hum. Mol. Genet. 9, 195–202 (2000).

CAS  PubMed  Google Scholar 

Costa, A. C., Walsh, K. & Davisson, M. T. Motor dysfunction in a mouse model for Down syndrome. Physiol. Behav. 68, 211–220 (1999).

CAS  PubMed  Google Scholar 

Escorihuela, R. M. Et al. Impaired short- and long-term memory in Ts65Dn mice, a model for Down syndrome. Neurosci. Lett. 247, 171–174 (1998).

CAS  PubMed  Google Scholar 

Dierssen, M. Et al. Murine models for Down syndrome. Physiol. Behav. 73, 859–871 (2001).

CAS  PubMed  Google Scholar 

Richtsmeier, J. T., Baxter, L. L. & Reeves, R. H. Parallels of craniofacial maldevelopment in Down syndrome and Ts65Dn mice. Dev. Dyn. 217, 137–145 (2000).

CAS  PubMed  Google Scholar 

Delcroix, J. D. Et al. Trafficking the NGF signal: implications for normal and degenerating neurons. Prog. Brain Res. 146, 3–23 (2004).

CAS  PubMed  Google Scholar 

Cooper, J. D. Et al. Failed retrograde transport of NGF in a mouse model of Down's syndrome: reversal of cholinergic neurodegenerative phenotypes following NGF infusion. Proc. Natl Acad. Sci. USA 98, 10439–10444 (2001).

CAS  PubMed  PubMed Central  Google Scholar 

Sago, H. Et al. Ts1Cje, a partial trisomy 16 mouse model for Down syndrome, exhibits learning and behavioral abnormalities. Proc. Natl Acad. Sci. USA 95, 6256–6261 (1998).

CAS  PubMed  PubMed Central  Google Scholar 

Sago, H. Et al. Genetic dissection of region associated with behavioral abnormalities in mouse models for Down syndrome. Pediatr. Res. 48, 606–613 (2000).

CAS  PubMed  Google Scholar 

Shinohara, T. Et al. Mice containing a human chromosome 21 model behavioral impairment and cardiac anomalies of Down's syndrome. Hum. Mol. Genet. 10, 1163–1175 (2001).

CAS  PubMed  Google Scholar 

Maroun, L. E., Heffernan, T. N. & Hallam, D. M. Partial IFN-α/β and IFN-γ receptor knockout trisomy 16 mouse fetuses show improved growth and cultured neuron viability. J. Interferon Cytokine Res. 20, 197–203 ( 2000).

CAS  PubMed  Google Scholar 

Epstein, C. J. Et al. Transgenic mice with increased Cu/Zn-superoxide dismutase activity: animal model of dosage effects in Down syndrome. Proc. Natl Acad. Sci. USA 84, 8044–8048 (1987). First description of single-gene transgenic mouse model to study the overexpression consequences of a HSA21 gene.

CAS  PubMed  PubMed Central  Google Scholar 

Chrast, R. Et al. Mice trisomic for a bacterial artificial chromosome with the single-minded 2 gene (Sim2) show phenotypes similar to some of those present in the partial trisomy 16 mouse models of Down syndrome. Hum. Mol. Genet. 9, 1853–1864 (2000).

CAS  PubMed  Google Scholar 

Sumarsono, S. H. Et al. Down's syndrome-like skeletal abnormalities in Ets2 transgenic mice. Nature 379, 534–537 (1996).

CAS  PubMed  Google Scholar 

Lejeune, J., Gautier, M. & Turpin, R. Études des chromosomes somatiques de neuf enfants mongoliens. C. R. Acad. Sci. 248, 1721–1722 (1959). A classic paper. The first description of trisomy 21.

CAS  Google Scholar 

Lyle, R., Gehrig, C., Neergaard-Henrichsen, C., Deutsch, S. & Antonarakis, S. E. Gene expression from the aneuploid chromosome in a trisomy mouse model of Down syndrome. Genome Res. 14, 1268–1274 (2004).

CAS  PubMed  PubMed Central  Google Scholar 

Reymond, A. Et al. Human chromosome 21 gene expression atlas in the mouse. Nature 420, 582–586 (2002). HSA21 gene expression atlas in the mouse.

CAS  PubMed  Google Scholar 

Gitton, Y. Et al. A gene expression map of human chromosome 21 orthologues in the mouse. Nature 420, 586–590 (2002). A gene expression map of HSA21 orthologues in the mouse.

CAS  PubMed  Google Scholar 

FitzPatrick, D. R. Et al. Transcriptome analysis of human autosomal trisomy. Hum. Mol. Genet. 11, 3249–3256 (2002).

CAS  PubMed  Google Scholar 

Mao, R., Zielke, C. L., Zielke, H. R. & Pevsner, J. Global up-regulation of chromosome 21 gene expression in the developing Down syndrome brain. Genomics 81, 457–467 (2003).

CAS  PubMed  Google Scholar 

Saran, N. G., Pletcher, M. T., Natale, J. E., Cheng, Y. & Reeves, R. H. Global disruption of the cerebellar transcriptome in a Down syndrome mouse model. Hum. Mol. Genet. 12, 2013–2019 (2003).

CAS  PubMed  Google Scholar 

Chrast, R. Et al. The mouse brain transcriptome by SAGE: differences in gene expression between P30 brains of the partial trisomy 16 mouse model of Down syndrome (Ts65Dn) and normals. Genome Res. 10, 2006–2021 (2000).

CAS  PubMed  PubMed Central  Google Scholar 

Barlow, G. M. Et al. Down syndrome congenital heart disease: a narrowed region and a candidate gene. Genet. Med. 3, 91–101 (2001).

CAS  PubMed  Google Scholar 

Korenberg, J. R. Et al. Down syndrome phenotypes: the consequences of chromosomal imbalance. Proc. Natl Acad. Sci. USA 91, 4997–5001 (1994).

CAS  PubMed  PubMed Central  Google Scholar 

Delabar, J. M. Et al. Molecular mapping of twenty-four features of Down syndrome on chromosome 21. Eur. J. Hum. Genet. 1, 114–124 (1993). Systematic attempt to define chromosomal trisomic regions resulting in Down syndrome phenotypes.

CAS  PubMed  Google Scholar 

Kuo, W. L. Et al. Detection of aneuploidy involving chromosomes 13, 18, or 21, by fluorescence in situ hybridization (FISH) to interphase and metaphase amniocytes. Am. J. Hum. Genet. 49, 112–119 (1991).

CAS  PubMed  PubMed Central  Google Scholar 

Armour, J. A., Sismani, C., Patsalis, P. C. & Cross, G. Measurement of locus copy number by hybridisation with amplifiable probes. Nucleic Acids Res. 28, 605–609 (2000).

CAS  PubMed  PubMed Central  Google Scholar 

Slater, H. R. Et al. Rapid, high throughput prenatal detection of aneuploidy using a novel quantitative method (MLPA). J. Med. Genet. 40, 907–912 (2003).

CAS  PubMed  PubMed Central  Google Scholar 

Deutsch, S., Choudhury, U. & Antonarakis, S. E. Detection of trisomy 21 and other aneuploidies by paralogous gene quantification. J. Med. Genet. (in the press).

Ishkanian, A. S. Et al. A tiling resolution DNA microarray with complete coverage of the human genome. Nature Genet. 36, 299–303 (2004).

CAS  PubMed  Google Scholar 

Epstein, C. J., Epstein, L. B., Weil, J. & Cox, D. R. Trisomy 21: mechanisms and models. Ann. NY Acad. Sci. 396, 107–118 (1982).

CAS  PubMed  Google Scholar 

Epstein, C. J. Mechanisms of the effects of aneuploidy in mammals. Annu. Rev. Genet. 22, 51–75 (1988).

CAS  PubMed  Google Scholar 

Epstein, C. J. Consequences of Chromosome Imbalance: Principles, Mechanisms, and Models, (Cambridge Univ. Press, New York, 1986).

Google Scholar 

Meeks-Wagner, D. & Hartwell, L. H. Normal stoichiometry of histone dimer sets is necessary for high fidelity of mitotic chromosome transmission. Cell 44, 43–52 (1986).

CAS  PubMed  Google Scholar 

Zwart, R. & Vijverberg, H. P. Four pharmacologically distinct subtypes of α4β2 nicotinic acetylcholine receptor expressed in Xenopus laevis oocytes. Mol. Pharmacol. 54, 1124–1131 (1998).

CAS  PubMed  Google Scholar 

Nelson, M. E., Kuryatov, A., Choi, C. H., Zhou, Y. & Lindstrom, J. Alternate stoichiometries of α4β2 nicotinic acetylcholine receptors. Mol. Pharmacol. 63, 332–341 (2003).

CAS  PubMed  Google Scholar 

Antoch, M. P. Et al. Functional identification of the mouse circadian Clock gene by transgenic BAC rescue. Cell 89, 655–667 (1997).

CAS  PubMed  PubMed Central  Google Scholar 

Alkema, M. J., van der Lugt, N. M., Bobeldijk, R. C., Berns, A. & van Lohuizen, M. Transformation of axial skeleton due to overexpression of bmi-1 in transgenic mice. Nature 374, 724–727 (1995).

CAS  PubMed  Google Scholar 

Heitzler, P. & Simpson, P. The choice of cell fate in the epidermis of Drosophila. Cell 64, 1083–1092 (1991).

CAS  PubMed  Google Scholar 

Semenza, G. L., Koury, S. T., Nejfelt, M. K., Gearhart, J. D. & Antonarakis, S. E. Cell-type-specific and hypoxia-inducible expression of the human erythropoietin gene in transgenic mice. Proc. Natl Acad. Sci. USA 88, 8725–8729 (1991).

CAS  PubMed  PubMed Central  Google Scholar 

Singaraja, R. R. Et al. Human ABCA1 BAC transgenic mice show increased high density lipoprotein cholesterol and ApoAI-dependent efflux stimulated by an internal promoter containing liver X receptor response elements in intron 1. J. Biol. Chem. 276, 33969–33979 (2001).

CAS  PubMed  Google Scholar 

Hoffman, S. & Edelman, G. M. Kinetics of homophilic binding by embryonic and adult forms of the neural cell adhesion molecule. Proc. Natl Acad. Sci. USA 80, 5762–5766 (1983).

CAS  PubMed  PubMed Central  Google Scholar 

Struhl, G., Struhl, K. & Macdonald, P. M. The gradient morphogen bicoid is a concentration-dependent transcriptional activator. Cell 57, 1259–1273 (1989).

CAS  PubMed  Google Scholar 

MacKay, V. L. Et al. Gene expression analyzed by high-resolution state array analysis and quantitative proteomics: response of yeast to mating pheromone. Mol. Cell. Proteomics 3, 478–489 (2004).

CAS  PubMed  Google Scholar 

Baptista, M. J. Et al. Heterotrisomy, a significant contributing factor to ventricular septal defect associated with Down syndrome? Hum. Genet. 107, 476–482 (2000).

CAS  PubMed  Google Scholar 

Ward, O. C., John Langdon Down (Royal Society of Medicine, London, 1998).

Google Scholar 

Wang, S. Y. Et al. A high-resolution physical map of human chromosome 21p using yeast artificial chromosomes. Genome Res. 9, 1059–1073 (1999).

CAS  PubMed  PubMed Central  Google Scholar 

Kong, A. Et al. A high-resolution recombination map of the human genome. Nature Genet. 31, 241–247 ( 2002).

CAS  PubMed  Google Scholar 

Lynn, A. Et al. Patterns of meiotic recombination on the long arm of human chromosome 21. Genome Res. 10, 1319–1332 (2000).

CAS  PubMed  Google Scholar 

Harrison, P. M. Et al. Molecular fossils in the human genome: identification and analysis of the pseudogenes in chromosomes 21 and 22. Genome Res. 12, 272–280 (2002).

CAS  PubMed  PubMed Central  Google Scholar 

Worton, R. G. Et al. Human ribosomal RNA genes: orientation of the tandem array and conservation of the 5′ end. Science 239, 64–68 (1988).

CAS  PubMed  Google Scholar 

Yamada, Y. Et al. A comprehensive analysis of allelic methylation status of CpG islands on human chromosome 21q. Genome Res. 14, 247–266 (2004).

CAS  PubMed  PubMed Central  Google Scholar 

Antonarakis, S. E., Lyle, R., Deutsch, S. & Reymond, A. Chromosome 21: a small land of fascinating disorders with unknown pathophysiology. Int. J. Dev. Biol. 46, 89–96 (2002).

CAS  PubMed  Google Scholar 

Olson, L. Et al. Down syndrome mouse models Ts65Dn, Ts1Cje, and Ms1Cje/Ts65Dn exhibit variable severity of cerebellar phenotypes. Dev. Dyn. 230, 581–589 (2004).

CAS  PubMed  Google Scholar 


Recognizing CDKL5 Deficiency Disorder - News-Medical.net

News-Medical speaks to Dr. Dan Lavery about the LouLou Foundation, a non-profit organization dedicated to CDLK5 Deficiency Disorder.

The Loulou Foundation is a private, non-profit foundation dedicated to developing meaningful therapeutics, and eventual cures, for CDKL5 Deficiency Disorder (CDD).

It was founded in 2015 by a family touched by CDD, and since its inception, the Foundation has focused on therapeutic development, which was lacking in the CDD community, and not on patient education and clinical standards of care, which have been very effectively served by patient organizations working at the national level.

What is CDD?

CDKL5 Deficiency Disorder (CDD) is a rare disorder which is caused by mutations in the CDKL5 gene.  Nearly all CDKL5 mutations leading to the disorder arise de novo and lead to loss of function of the CDKL5 gene.

Patients living with CDD show a significant neurodevelopmental delay, including severe hypotonia, motor and visual impairment, and little to no communication skills.  In addition, CDD patients suffer gastrointestinal, respiratory, and sleep issues, and a complex profile of epileptic seizures which are, in general, poorly controlled by medications.  Most CDD patients will thus require near-constant care for their entire lives.

Recent estimates place the incidence of CDD at approximately one in 40,000 live births, making it one of the most common monogenic epileptic disorders.  Several hundred CDD patients have been diagnosed worldwide, but many thousands more remain to be identified.

While several clinical trials are underway for novel therapeutics for CDD, there are no current therapies for the neurodevelopmental symptoms associated with CDD.

Image Credit: Evgeniy Kalinovskiy/Shutterstock.Com

90% of children affected by CDKL5 are girls. Why is this?

It is believed that this is because the CDKL5 gene is located on the X chromosome.  As girls have two X chromosomes and boys have only one, the expression of the two X chromosomes in girls is balanced to the single copy in boys through a process called X inactivation, in which one of the two X chromosomes in each cell is randomly but stably silenced.

In girls with CDD, carrying in each cell a mutant CDKL5 gene on one X chromosome and an unmutated, "wild type" CDKL5 gene on the other, X inactivation means that half of all of their cells express the mutant CDKL5 gene and the other half of their cells express the unmutated CDKL5 gene.

In boys carrying a CDKL5 mutation on their single X chromosome, all cells express the mutant CDKL5 gene.  One hypothesis is that since in boys, all cells are expressing the mutant CDKL5 gene, they are in general more severely affected than girls, and many may not survive to term.  This could explain the skewing of the population of CDD patients toward girls (80-90%) over boys (10-20%).

Image Credit: Chiari VFX/Shutterstock.Com

Why is it important to get an early diagnosis of CDD?

Early diagnosis of CDD will allow the CDD patient and family to benefit from a more defined clinical treatment regimen, particularly as more therapies developed specifically for CDD become available; and may avoid testing treatments that are known to be contraindicated in CDD patients.

Early diagnosis can also lead to inclusion in robust therapy programs (physical, vision, occupational, etc.) that can be of greater benefit with earlier intervention.

Early diagnosis can also allow families to connect with the CDD community, to learn from and share with other families living with CDD, to become active in the community, and to learn about potential clinical studies involving CDD patients and families.

Why was it important to receive recognition for this disease from the WHO and get an ICD-10 code?

There are many advantages to having a specific ICD-10 code assigned by the WHO to CDD.  The first is that it allows clinicians to identify CDD patients in medical records using an unambiguous code.

In the past, a series of different codes could have been used to classify CDD in a patient's medical records, including "generalized epilepsy," "atypical Rett syndrome," or even just "genetic mutation."  This made tracking of patients, medications, and therapies for CDD virtually impossible.

Now, with a unique ICD-10 code, all CDD patients can be identified and tracked, for epidemiological and clinical therapeutic studies.  Also, an ICD-10 code is the recognition that CDD is a distinct, clinically and genetically defined disorder, and should not be confused with or lumped together with some larger syndromic diagnoses like atypical Rett syndrome or West syndrome.

Image Credit: LouLouFoundation

As you now have an ICD-10 code for this disease, do you believe this will help in monitoring the number of people with this disease?

Yes, this will allow us to track new diagnoses, and with some effort, it may also help us identify and track patients with CDD who might have never received an accurate diagnosis.

What does this classification mean for people living with CDD? How will this improve their quality of life?

For patients and families living with CDD, the ICD-10 code allows them to have a clearly defined, distinct diagnosis that allows them to access truly relevant information from their clinicians and other families living with CDD.  This alone can improve the quality of life of the patient and family.

However, the specific ICD-10 code for CDD vastly improves the quality and scope of epidemiological and clinical studies on the disorder, including offering the families the opportunity to learn about clinical trials for new treatments for CDD.

Already our community has one active Phase 3 and several active Phase 2 trials specific to patients with CDD.

What are the next steps in your research in CDD?

As mentioned, there are already Phase 2 and Phase 3 studies ongoing with CDD patients for the evaluation of next-generation anti-seizure medications, which might also impact other aspects of the disorder beyond seizures.

Likewise, there are two publicly announced pre-clinical programs at experienced rare disease companies that are using virus-based gene therapy approaches to offer potentially disease-modifying therapeutics for CDD.

In addition, more research is being conducted to learn more about the basic mechanisms of the disorder and to discover novel pathways to target for improved treatment of the disorder.

Where can readers find more information?

Read more about the LouLou Foundation

CDKL5 Research

Read more about CDKL5 Deficiency Disorder

CDKL5 Alliance, an umbrella group of CDKL5 patient groups worldwide, which help families connect with their local CDKL5 community.

About Dan Lavery

Daniel J Lavery, Ph.D., is the Chief Scientific Officer at the Loulou Foundation, and the Director of the CDKL5 Program of Excellence in the Orphan Disease Center at the Perelman School of Medicine, University of Pennsylvania, USA.

Before joining the Loulou Foundation in May 2017, Dan was Science Director, Discovery Systems Biology, at CHDI, a private foundation dedicated to Huntington's disease therapeutic development.

Previously, Dan has worked in pharma and biotech including GSK and Purdue Pharma, studying CNS disorders such as neuropathic pain, schizophrenia, and ALS, using systems biology and genome-scale data mining to identify novel disease pathways, and developing repurposing strategies to drive rapid clinical development.

Dan trained at Johns Hopkins University, Mount Sinai School of Medicine, and the University of Geneva, Switzerland.

He is the author or co-author of over 30 primary research articles, reviews, book chapters, and patents.






Comments

Popular posts from this blog

Diagnosis and management of vascular Ehlers-Danlos syndrome: Experience of the UK national diagnostic service, Sheffield | European Journal of Human Genetics

Non-invasive prenatal testing: a revolutionary journey in prenatal testing

The evolving role of genetic tests in reproductive medicine