Oculodentodigital Dysplasia
Patient Information
Characteristics
Background and History
This is a malformation syndrome with highly variable clinical features involving the eyes, skeletal system, teeth, and hair.
Clinical Correlations
Most patients have small, deep-set eyes and palpebral fissures are small. A few patients have had cataracts and glaucoma. Abnormal eye movements and crossing of the eyes are sometimes present. The nose has been described as “pinched” since it often appears narrow and peaked. The teeth are often small with a defective enamel covering. The hair is thin and sparse and nails may appear malformed. The ribs and bones of the arms and legs are widened. The fingers and toes are often webbed and constituent bones may be missing or underdeveloped. Neurologic deficits such as spasticity may be seen in some patients but the pattern is not consistent.
Genetics
Inheritance
A single mutant gene seems to cause this disorder. Family patterns of inheritance are consistent with both autosomal dominant and autosomal recessive inheritance.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
Diagnosis and Prognosis
The diagnosis is based on the unique combination of bone and eye findings in the presence of typical facial features. It usually requires the collaborative efforts of geneticists, pediatricians and ophthalmologists. No treatment is available for the general disorder although the presence of cataracts and glaucoma may require specific therapy. Neurologic deficits are usually relatively mild.
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