Atypical Glycine Encephalopathy

A rare form of glycine encephalopathy presenting disease onset or clinical manifestations that differ from neonatal or infantile glycine encephalopathy.

Epidemiology

The prevalence of atypical glycine encephalopathy is not known. Approximately 20 cases have been reported to date.

Clinical description

Symptoms are mostly non-specific and are not similar to the severe neurological symptoms observed in neonatal and infantile GE (see these terms). Some patients have milder disease with onset from late infancy to adulthood, while others have rapidly progressive severe disease often of late onset. It also includes patients with transient hyperglycinemia, whose symptoms in neonatal period resemble those of neonatal form. Manifestations include cognitive decline, behavioral disorders, ataxia, peripheral neuropathy and optic atrophy.

Etiology

Etiology of atypical glycine encephalopathy remains largely unknown. It was reported that some patients had mutations in genes encoding GCS components.

Genetic counseling

Mode of inheritance has not been identified in most of patients with atypical glycine encephalopathy