What is the diagnosis and treatment for Congenital Disorder of Glycosylation (CDG) type 1A, also known as Carbohydrate-Deficient Glycoprotein Syndrome type 1A (CDGS 1A)?

From the Research

Diagnosis of Congenital Disorder of Glycosylation (CDG) type 1A

• The diagnosis of CDG type 1A is based on the clinical findings of characteristic fat distribution, neurologic impairment, and developmental delay, combined with the biochemical finding of cathodally migrating serum glycoproteins, transferrin in particular, on isoelectric focusing 1.
• Isoelectrofocusing of serum transferrin is the most widely used screening test for CDG type 1A 2.
• The abnormal pattern of transferrin glycosylation and phosphomannomutase activity assay can confirm the diagnosis of CDG type 1A 3.

Treatment of Congenital Disorder of Glycosylation (CDG) type 1A

• Unfortunately, an efficient treatment is still not available for CDG type 1A patients 3.
• No curative or effective treatment is available for neurological CDG, including CDG type 1A 2.
• Palliative care and support is the most that can be offered to patients with CDG type 1A 1.
• Short-term mannose therapy has been tried, but it does not support a benefit of mannose to the deficient glycosylation of CDG type 1A patients 4.

Clinical Characteristics of Congenital Disorder of Glycosylation (CDG) type 1A

• CDG type 1A is characterized by defective glycosylation, resulting from a deficiency of phosphomannomutase (PMM), the enzyme that converts mannose 6-phosphate to mannose 1-phosphate in the synthesis of GDP-mannose 5.
• The clinical presentation of CDG type 1A includes developmental delay, failure to thrive, inverted nipples, and abnormal fat pads 3.
• Neurological signs and symptoms include psychomotor retardation, epilepsy, hypotonia, hyporeflexia, strabismus, retinitis pigmentosa, polyneuropathy, myopathy, and cerebellar hypotrophy/hypoplasia 2.