Congenital Disorders of Glycosylation

Congenital disorders of glycosylation (CDG), a group of autosomal recessive multisystem disorders, is caused by deficient activity of enzymes involved in glycosylation of proteins. Several carbohydrate-deficient glycoprotein diseases have been distinguished. Among them, CDG type Ia is the most common. It is caused by the deficient activity of the enzyme phosphomannomutase. The mutant gene maps to chromosome 16.

The disease affects chiefly infants and children and presents with many and various features:

• Somatic—Growth retardation, inverted nipples, abnormal fat pads

• Skeletal—Kyphosis, scoliosis

• Ocular—Strabismus, retinitis pigmentosa

• Neurologic—Mental retardation, hypotonia, cerebel-lar ataxia, stroke-like episodes, and polyneuropathy

• Visceral—Hepatic and renal dysfunctions

• Hematologic—Coagulopathy

MRI demonstrates cerebellar and pontine atrophy. Adult patients present with hypogonadism.

Grossly, the cerebellum and the pons are severely atrophic. Histology shows olivopontocerebellar hypo-plasia or atrophy characterized by loss of the nuclei pontis and transverse pontine fibers, loss of Purkinje cells, and loss of neurons in the olivary nuclei. The liver shows cirrhosis, fibrosis, and fatty infiltration.

0 0

Post a comment