OMIM ID:
Encephalopathy, Progressive, with Amyotrophy and Optic Atrophy
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Optic atrophy is present.
Systemic Features
This is a progressive neurodegenerative condition in which hypotonia and delayed development are evident between birth and 14 months of age. Developmental milestones, if attained, soon regress accompanied by distal amyotrophy, cognitive impairment that may be severe, ataxia, spastic tetraplegia, dysarthria, and scoliosis. Seizures often occur.
Brain imaging reveals cerebellar and cerebral atrophy. Iron accumulation may be seen in the pallidum and substantia nigra. The corpus callosum appears abnormally thin. Muscle biopsy shows evidence of denervation atrophy.
Genetics
Inheritance
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.