PEHO syndrome

PEHO syndrome is a progressive encephalopathy with edema, hypsarrhythmia and optic atrophy. It is a very rare disease, one of the Finnish heritage diseases, although approximately half of the cases reported so far are not-Finnish and have been described worldwide .

It has been suggested that it may also be present in Australian and American populations.

Aetiology

A mutation in the ZNHIT3 gene - a nuclear zinc finger protein involved in transcriptional regulation and in small nucleolar ribonucleoprotein particle assembly has been shown to be the cause of the Finnish-type of PEHO syndrome. However, the syndrome appear to be genetically heterogeneous and it might reflect an underlying genetic tubulinopathy, with biallelic mutations in the gene PRUNE1 also identified in non-Finnish patients with PEHO syndrome.

Diagnosis

• Diagnosis is mainly clinical and depends on the presence of the following diagnostic criteria: early-onset severe hypotonia
• The occurrence of seizures, infantile spasms and hypsarrhythmia after the first two weeks of life
• Onset of optic atrophy before two years of age, and failure to obtain any of the milestones for motor, visual and language development.
• An additional criterion is demonstration of cerebellar and brainstem atrophy by MRI.
• A significant number of patients have been described who displayed most of the diagnostic criteria and features of PEHO syndrome, but did not appear to have cerebral atrophy on MRI, lacked the ophthalmologic signs and showed no reduction in CSF IGF-1 levels.
• This group of patients was diagnosed with PEHO-like syndrome.

Antenatal diagnosis Prenatal diagnosis is not available but early diagnosis is essential for genetic counseling of affected families.

Treatment

Treatment is symptomatic only. The infantile spasms are refractory to antiepileptic drugs or adrenocorticotropic hormone (ACTH) therapy.

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Classification	ICD-10: G31.8 OMIM: 260565 DiseasesDB: 33582