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. 2017 Jun;173(6):1620-1624.
doi: 10.1002/ajmg.a.38235. Epub 2017 Apr 19.

Three families with mild PMM2-CDG and normal cognitive development

Mari-Anne Vals  1   2   3 , Eva Morava  4   5 , Kai Teeäär  6 , Riina Zordania  1 , Sander Pajusalu  1   2 , Dirk J Lefeber  7 , Katrin Õunap  1   2
Affiliations

Three families with mild PMM2-CDG and normal cognitive development

Mari-Anne Vals et al. Am J Med Genet A. 2017 Jun.

Abstract

Congenital disorders of glycosylation (CDG) are caused by defective glycosylation of proteins and lipids. PMM2-CDG is the most common subtype among the CDG. The severity of PMM2-CDG is variable. Patients often have a recognizable phenotype with neurological and multisystem symptoms that might cause early death. We report six patients from three families who are diagnosed with a clinically mild PMM2-CDG and have normal cognitive development. All these patients had delayed gross motor skills with mild-to-moderate neurological findings. Cerebellar hypoplasia was detected in all siblings for whom brain MRI was performed. In 5/6 children the Wechsler Intelligence Scale for Children (WISC) showed normal cognitive development with full scale IQ scores ranging from borderline to average. Four patients were diagnosed with PMM2-CDG at the age of 8 years or later as their neurological symptoms were quite mild and they had been able to participate in regular school programs. We report patients with p.Val231Met/p.Arg239Trp and p.Ile120Thr/p.Gly228Cys genotypes which may cause milder variants of PMM2-CDG.

Keywords: PMM2-CDG; cerebellar hypoplasia; congenital disorders of glycosylation; mild phenotype.

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