Two novel missense mutations observed in nonketotic hyperglycinemia.
Nonketotic hyperglycinemia, also known as glycine encephalopathy, is an autosomal recessive disorder of an inborn error of the glycine metabolism, caused by deficiency in the mitochondrial glycine cleavage enzyme. The majority of cases are caused by mutations in P-protein, one of the four components of the glycine cleavage enzyme, glycine decarboxylase. We describe a male neonate with hypotonia, hiccups, and persistent apnea, but without seizures. The patient's glycine level in cerebrospinal fluid and plasma was 328.3 nmol/mL (reference value, 2.2-14.2 nmol/mL) and 1439 nmol/mL (reference value, 232-740 nmol/mL), respectively. The cerebrospinal fluid/plasma ratio of 0.228 represented an increase (normal range, <0.04). Two novel heterozygous missense mutations (c.1130C>T (p.A377V) and c.2081_2088del (p.A694DfsX11) in exons 8 and 18) in the glycine decarboxylase gene confirmed the diagnosis of nonketotic hyperglycinemia.
Department of Pediatrics, College of Medicine, Chung-Ang University, Dongjak-gu, Seoul, Korea.
In Ae
IA
Yoon
Na Mi
NM
Lee
Byoung Hoon
BH
Yoo
Byong Sop
BS
Lee
Han-Wook
HW
Yoo
D001483:Base Sequence; D005091:Exons / Q000235:genetics; D006801:Humans; D020158:Hyperglycinemia, Nonketotic / Q000175:diagnosis* / Q000235:genetics*; D007231:Infant, Newborn; D008297:Male; D008969:Molecular Sequence Data; D020125:Mutation, Missense / Q000235:genetics*