Introduction:

Glycine encephalopathy (GE), also known as non-ketotic hyperglycinemia (NKH), is a rare inborn error of glycine

metabolism caused by a defect in glycine cleavage system, a multi-enzyme complex located in mitochondrial membrane. This defect

results in elevated glycine concentration in plasma and cerebrospinal fluid (CSF). Clinical manifestations vary from severe lethargy,

hypoactivity and apneic episodes in the neonatal form, mild or moderate psychomotor delay and seizures in the infantile form, and

abnormal behaviors, ataxia and choreoathetoid movements in late onset form. More than 50

GLDC

mutations were found, reflect-

ing large heterogeneity of the gene.

Methods:

We describe the clinical, biochemical and molecular characteristics of three Palestinian siblings who have distinct clin-

ical phenotypes. Molecular study was performed utilizing standard Polymerase Chain Reaction (PCR) amplification then direct

DNA sequencing for the affected family members.

Results:

Their phenotypes included severe symptoms in neonatal period, infantile onset of seizure and psychomotor delay and a

mild late-onset form with speech delay at age 20 months. All siblings were homozygous for a novel mutation Y164H in exon 4 of

GLDC

gene. The described novel homozygous variant in our study is predicted deleterious and pathogenic.

Conclusions:

This article further expands the genetic spectrum of glycine encephalopathy and adds an evidence of the clinical

heterogeneity of glycine encephalopathy even in siblings with identical mutation.

Title

Brain and Development

Publisher

Elsevier

Publisher Country

Netherlands

Publication Type

Prtinted only

Volume

--

Year

2017

Pages

1-5