Retinal Dystrophy, Cataracts, and Short Stature
Patient Information
Characteristics
Background and History
Retinal degeneration (dystrophy) can result from a variety of gene mutations. Most are conditions that only involve the eye but several including this one have systemic signs as well.
Clinical Correlations
General development delays are evident in early childhood with lack of fine movement and coordination skills and learning difficulties. During the first decade of life children develop increasing difficulties with night vision although daytime vision remain good, at least through the first two decades. However, special tests such as the electroretinogram (ERG) show generalized dysfunction of the retinal rods and cones. Examination of the retina shows changes in pigmentation, a reflection of the underlying retinal deterioration. Cataracts may be diagnosed in young children.
Individuals are short in stature from childhood. The face is said to be characteristic with upslanting eyelid openings and the cheek bones are somewhat flat. The teeth are somewhat malformed with wide spaces between them.
Genetics
Inheritance
This is an autosomal recessive condition in which affected individuals have mutations in both copies of a gene. The parents are clinically normal carriers of a single mutation but together they confer a 25% risk of transmitting both copies to each of their children.
Pedigree
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
Pediatricians, eye doctors (ophthalmologists) and dentists might collaborate on the diagnosis and care. Nothing is known about longevity and no treatment is known for the basic disease. However, patients could benefit from special education, removal of cataracts, and correction of the dental malformations. Physical therapy may also be helpful.
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