Genetic disorders

Birth defect syndromes

These are conditions in which a child is born with one or more birth defects, and often specific facial characteristics, which indicate the presence of a specific syndrome. Many of these syndromes have a genetic basis, but some do not. Some examples are Brachman-de Lange syndrome, fetal alcohol syndrome.

Chromosome abnormalities

These are conditions which result from the presence of extra chromosomal material or from a piece of a chromosome missing. Some of the more common disorders are:

  • Down syndrome (trisomy 21)
  • trisomy 18
  • trisomy 13
  • Turner syndrome
  • Klinefelter syndrome

Most (but not all) of these conditions result in specific types of birth defects and mental retardation.

Marfan syndrome

People with Marfan syndrome are unusually tall, and have disproportionately long arms and legs. Curvature of the spine (scoliosis) is quite common and the joints may be very lax and flexible. The most serious problems in Marfan syndrome relate to widening of the main artery which brings blood from the heart to the rest of the body (the aorta) and dislocation of the lenses of the eye.

Metabolic disorders

These are conditions in which the body is unable to normally perform some aspect of metabolism. Most of them result from lack of a functioning enzyme involved in a specific and necessary biochemical reaction within the body. Many of these disorders are quite rare and unfamiliar; some of the more common ones are:

  • phenylketonuria (PKU)
  • galactosemia, urea cycle disorders
  • glycogen storage diseases
  • mucopolysaccharidoses
  • Tay-Sachs disease
  • Gaucher disease

Neurofibromatosis-1

This dominantly inherited condition is characterized by the development of multiple benign tumors arising from the cells surrounding nerves. The tumors can appear anywhere, but are most commonly noticed in the skin. Learning disabilities are also very common, and brown patches of skin (café-au-lait spots) are also very common.

Skeletal dysplasias

Most skeletal dysplasias are diagnosed because of short stature or dwarfism. These conditions result from mutations that affect the growth and development of cartilage and bone. The bones may not only be short, but they may be abnormally shaped, as well. The most common of these disorders, achondroplasia, affects 1 in 10,000 people.