Peroxisomol Fatty Acyl-CoA Reductase 1 Disorder
Patient Information
Characteristics
Background and History
This complex condition is the result of a hereditary enzyme defect resulting in widespread physical and mental problems.
Clinical Correlations
Cataracts can be present at birth and infants are ‘floppy’. Later physical and mental delays are evident and seizures can occur. The facial appearance is described as coarse with high bushy eyebrows, large ears, a thin upper lip, and flattening of the nasal bridge. The skull appears small as its growth and development are delayed. The limbs become stiff as spasticity sets in. Some individuals are unable to walk and they may have significant cognitive deficits.
Genetics
Inheritance
This condition has an autosomal recessive pattern of transmission. An enzymatic defect results from mutations in a specific gene that must have a mutation in both members of a pair, one of which is contributed by each of the clinically normal carrier parents. Such couples confer a 25% risk of occurrence 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
Only a few individuals with this disorder have been reported and the natural history is unknown. Features are present at birth but they are nonspecific making neonatal diagnosis difficult. Pediatricians and neurologists are most likely to make the diagnosis in early childhood. A test on red blood cells may reveal decreased amounts of plasmalogen. Care is primarily supportive in emphasis although physical therapy and special education may be helpful in selected individuals. It is possible to surgically remove cataracts but the decision to do so in this disorder must be individualized.
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