OMIM ID:
Retinal Dystrophy and Obesity
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
The age of onset of symptoms is unknown but based on the report of a single family with three affected sibs, it may occur early in the second decade. Patients may note some loss of night vision and the visual fields are restricted. The ERG responses are consistent with a generalized rod-cone dystrophy. Fundoscopy reveals a generalized RPE atrophy together with arteriolar attenuation, peripheral pigmentary mottling and scattered white dots. A nonspecific dyschromatopsia can be demonstrated but the fovea is relatively normal and central acuity is remarkably good. Little is known about disease progression but an 18 year old male reported decreasing vision since the age of 11 years.
Systemic Features
Obesity and a high BMI may be present.
Genetics
Inheritance
Homozygous mutations in the TUB gene (11p15) segregated with this disorder in a sibship from a consanguineous family.
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.