Case Report of 3-Phosphoglycerate Dehydrogenase Deficiency: A Baby with Severe Microcephaly, Psychomotor Delay, and Seizures

Abstract This is a case presentation of a patient with microcephaly, severe developmental delay, and refractory seizures who was found to have low levels of serum serine and glycine. Exome sequencing revealed a homozygous mutation in the 3-phosphoglycerate dehydrogenase deficiency (PHGDH) gene at chromosome 1p12. Cerebrospinal fluid (CSF) serine level was subsequently found to be low in keeping with the genetic diagnosis. L-glycine and L-serine supplements were started, which led to improvement in seizure burden. In this rare condition, seizure impact and psychomotor development can improve with supplementation of L-serine and L-glycine; therefore, timely diagnosis is crucial in the management of these patients. Our case also highlighted the role of molecular genetic testing in cases where CSF sampling is difficult, when there are typical clinical features of PHGDH. PHGDH is a rare disorder but should be considered in patients with microcephaly and refractory epilepsy as supplementation with serine may be beneficial.