Chromosomal microarray analyses from 5778 patients with neurodevelopmental disorders and congenital anomalies in Brazil

Diagnosing Down Syndrome, Cystic Fibrosis, Tay-Sachs Disease And Other Genetic Disorders

Sometimes, a pediatrician will suspect that a child has a genetic disorder based on the child's symptoms or on the presence of dysmorphic features. For example, if a child has coarse facial features and developmental delays, a pediatrician may have reason to believe that the child has a form of mucopolysaccharidosis. Mucopolysaccharidosis is a family of diseases caused by an enzyme deficiency that leads to the accumulation of glycosaminoglycans (GAGs) within the lysosomes of cells. In one particular variant of this disease known as mucopolysaccharidosis I (MPS I), a deficiency of the enzyme alpha-L-iduronidase causes a build up of GAGs in tissues and organs, which in turn leads to a host of signs including skeletal deformities, coarse facial features, enlarged liver and spleen, and mental deficiencies. Because of the progressive nature of MPS I, a child might not exhibit noticeable symptoms until one to three years of age or even later, depending on severity.

There are a number of reasons that a pediatrician might refer a child to see a geneticist. Geneticists can confirm or rule out a physician's diagnosis based on the findings of a physical exam and various tests. In the case of a child with suspected MPS, if the enzymatic deficiency associated with the disorder is confirmed via testing, DNA analysis may also be performed to determine the exact genetic mutation causing the disorder. Because MPS I is inherited in an autosomal recessive fashion, identification of the mutation can allow the family to undergo carrier screening, as well as prenatal or preimplantation diagnosis in any future children.

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