PEHO Syndrome
Patient Information
Characteristics
Background and History
This is a severe heritable disorder of the nervous system found most commonly in Finland.
Clinical Correlations
Infants are born of normal size but skull growth soon falls behind. There is often excess fluid (edema) seen in the face and limbs. Babies are weak and ‘floppy’ with poor muscle tone although their reflexes may be exaggerated in the limbs. They do not visually fixate on objects and this may be noted at birth or soon thereafter. The optic nerve is abnormally pale. Normal developmental milestones such as speech and sitting are not achieved. Infantile spasms can be seen soon after birth and some newborns develop generalized seizures. They feed poorly.
MRI imaging of the brain reveals lack of normal development in several brain structures (cerebellum and brainstem).
Genetics
Inheritance
The family pattern of children with this condition suggests autosomal recessive inheritance that result from two mutations in a specific gene. Carriers such as parents do not have the neurological disease. However each of their children have a 25% risk of this condition.
This disorder has many clinical similarities to the PEHO-like syndrome described elsewhere in this database.
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
Pediatricians and neurologists are most likely to collaborate in the diagnosis which can be suspected in the neonatal period. An ophthalmologist can confirm the abnormal optic nerve and document the absence of vision.
There is no treatment for this congenital condition and children usually do not live beyond the first years of life. General supportive care should be given. Physical therapy may help in preventing joint contractures. Supplemental feeding should be considered.
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