Clinical Characteristics
Ocular Features
Dense white cataracts have been diagnosed as soon as 2 weeks after birth.
Systemic Features
No dysmorphic features or psychomotor deficits have been found.
Genetics
Inheritance
Homozygous mutations in the SIPA1L3 gene (19q13.1-q13.2) were found in a consanguineous German family in which 2 of 3 female sibs were affected. The parents were phenotypically normal but heterozygous for the mutation.
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.