Opacification of the lens in the eye resulting in loss of transparency is called a cataract. Cataracts that appear in infants or childhood are generally called congenital or developmental cataracts. All newborns should have a complete eye examination since early detection and treatment can be important to prevent lazy eye (amblyopia). Cataracts may arise from a variety of causes including various general developmental syndromes, intrauterine infections such as rubella, chromosomal abnormalities, or inherited disorders of metabolism such as galactosemia. About one-fourth are familial and these are usually caused by single gene mutations. Inherited forms of cataracts are usually bilateral. Some congenital cataracts are part of more generalized disorders such as this one.
Cataracts and small corneas (windshield of the eye) are present at birth. Vision is poor from the beginning and dancing of the eyes (nystagmus) is virtually always present.
During childhood the facial deformities become evident. These consist of a coarse facies with thickening of the lips, a prominence of the midface, and an apparently small jaw. The teeth are directed forward. A delay in motor skills and mental functioning also is evident during the first decade of life. Weakness in the legs begins before that in the arms and often there is some unsteadiness in the trunk and during walking. There may also be some deficiency in touch. Purposeless movements of the hands and a writhing restlessness of the fingers are present. MRI shows some progressive loss of brain and spinal cord tissue. Most patients have some cognitive deficits and are slow learners. Short stature is seen in nearly all individuals. A viral illness may lead to severe breakdown of muscle tissue and severe weakness ensues. Spinal, hand, and foot deformities are common.
This is an autosomal recessive disorder requiring the presence of mutations in both genes. Parents who carry a single copy of the mutation are generally normal, but when both carry the mutation they can expect that on average one out of four of their children will inherit this disease.
The ophthalmologist may be the first to diagnose this disorder because of the presence of cataracts and the small corneas in newborns. A neurologist will be able to confirm the diagnosis. The visual prognosis is poor even though some children have had cataract surgery. Most individuals are severely disabled by the fourth decade of life. There is no treatment for the neurological disease although physical therapy might be helpful.