You are examining a 2-year-old child who has begun having trouble walking and stumbles and falls frequently. Additional manifesting symptoms are developmental delay, muscle weakness, and speech and vision impairment. Muscle biopsy results indicate the patient has a deficiency in functional α-dystroglycan. The clinical signs in this patient would most likely be associated with a defect in which of the following pathway?

Question

Quizplus · Accepted Answer

O-mannosylation has been identified on α-dystroglycan (α-DG) from nerve and muscle, chondroitin sulfate proteoglycans, and total glycopeptides from brain tissue. Clinically, O-mannosylation of α-DG is the most significant as evidenced by the constellation of symptoms that result from defects in the processes of O-mannosylation. Defective O-mannosylation is associated with a group of autosomal recessive muscular dystrophies termed congenital muscular dystrophies (CMDs). In addition to muscle dysfunction, these CMDs are also associated with variable brain and ocular abnormalities.

You Are Examining a 2-Year-Old Child Who Has Begun Having