OMIM ID:
Mitochondrial Short-Chain Enoyl-CoA Hydratase 1 Deficiency
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
The ocular phenotype has not been thoroughly studied. Nystagmus has been reported in several infants.
Systemic Features
Evidence of severe psychomotor retardation is evident at birth or shortly thereafter. Neonatal hypotonia with a poor suck reflex and episodic apnea is evident. Spasticity may become evident later. Brain imaging shows T-weighted hyperintensity areas in the basal ganglia resembling Leigh syndrome lesions. The corpus callosum appears thin. Serum and CSF lactate is elevated and decreased activity of the pyruvate dehydrogenase complex is present.
Infants do not achieve normal developmental milestones such as speech or sitting unsupported and several have died early in childhood from cardiorespiratory failure, possibly related to a combined mitochondrial respiratory chain dysfunction.
Genetics
Inheritance
The transmission pattern in several families is consistent with autosomal recessive inheritance. Compound heterozygous mutations have been found in the ECHS1 gene (10q26.3).
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.