Congenital disorder of glycosylation (CDG) type Ie. A new patient.

ABSTRACT

CDG Ie is caused by a deficiency of dolichol-phosphate-mannose synthase 1 (DPM1), an enzyme involved in N-glycan assembly in the endoplasmic reticulum. Three proteins are known to be part of the synthase complex DPM 1, DPM2 and DPM3. Only mutations in DPM1, the catalytic subunit, have been described in three families. One was homozygous for the c274C>G (R92G) mutation in DPM1 and two others were compound heterozygous for R92G and a c628delC deletion or a c331-343del13, respectively. Clinical features were a severe infantile encephalopathy, early intractable seizures, acquired microcephaly, and some dysmorphic features. We report a patient with milder symptoms microcephaly, dysmorphic features, developmental delay, optic atrophy, and cerebellar dysfunction without cerebellar atrophy. The patient is homozygous for a new mutation in exon 9 of the DPM1 gene (c742T>C (S248P)). Our findings extend the spectrum of CDG Ie.