OMIM ID:
Peroxisomol Fatty Acyl-CoA Reductase 1 Disorder
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
At least some patients have cataracts which may be congenital in origin. Highly arched eyebrows are part of the facial dysmorphism.
Systemic Features
Neonatal hypotonia is common while postnatal psychomotor development, somatic growth delay, microcephaly, and seizures become evident later. The coarse facial dysmorphism includes large ears, a flattened nasal root, thin upper lip, a long philtrum, and a flattening of the nasal root. Cognitive deficits are often present and some individuals have significant mobility problems.
Red blood cell plasmalogen may be decreased.
Genetics
Inheritance
This condition results from homozygous or compound heterozygous mutations in FAR1 gene (11p15.2) resulting in complete loss of enzyme activity consistent with a defect in peroxisomes.
There is some clinical resemblance to rhizomelic chondrodysplasia punctata (215100) in which congenital cataracts also occur but lacks the skeletal features and results from a different 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.