Identification of Compound Heterozygous DPM1 Variants in a Pediatric Patient With Congenital Disorder of Glycosylation Type Ie.

Congenital disorders of glycosylation (CDG) constitute a group of rare genetic metabolic diseases caused by defects in the synthesis and modification of oligosaccharides. CDG-Ie is a rare subtype caused by mutations in the DPM1 gene. We describe a female patient who presented with ocular abnormalities, motor retardation, hypotonia, hepatic dysfunction, elevated creatine kinase, abnormal electroencephalogram (EEG), and abnormal cranial magnetic resonance imaging (MRI) findings, which have been reported in previous cases. However, we note that this case had previously undescribed findings of the CDG-Ie phenotype, including hearing abnormalities and decreased parathyroid hormone levels. She carries compound heterozygous variants in the DPM1 gene: a paternal [c.1A>G (p.M1V)] start codon mutation and a maternal [c.371A>G (p.H124R), (NM_003859)] missense variant. We present the 12th case known worldwide to date.