Genetic Studies of Congenital disorders of glycosylation

Congenital disorders of glycosylation (CDG) are predominantly multisystem diseases. More than ۱۴۰ different genetic defects caused deficiency of enzymes involved inproteins glycosylation. In this case series, we describe five cases of different kinds of CDGs that proved with genetic studies (Whole Exome Sequencing-WES). Case presentation: Case ۱. A ۱۰ years old boy who’s the only child of consanguineous parents. He had muscular hypotonia, intellectual disability, photophobia, epilepsy,athetotic movements, inverted nipples and abnormal subcutaneous fat distribution, knee contracture and lips with whistling posture. The WES was performed and the result was a homozygous variant in exon ۹ of the NGLY۱ gene. Case ۲. The patient was a ۱۲ years old boy, the second child of consanguineous parents. His sister and his cousin had intellectual disability. He had muscular hypotonia, intellectual disability, developmental delay and epilepsy. In brain MRI we found generalized brain atrophy. The WES was performed and the result was a homozygous variant in exon ۱۱ of the ALG۱ gene. Case ۳ to ۵. Three children of a family, two girls and one boy, with ADHD, intellectual disability and epilepsy were presented. One girl had microcephaly and the other children had normal head circumference. Parents were not consanguineous. The WES was performed and the result was a homozygous variant in exon ۱۱ of the ALG۱ gene.

Keywords:

Congenital Disorders of Glycosylation , CDG , Whole Exome Sequencing , ALG۱ , NGLY۱.