What are the signs and symptoms of POMT1 and POMT2 congenital muscular dystrophy (CMD)?

Updated: Jul 03, 2019
  • Author: Emad R Noor, MBChB; Chief Editor: Amy Kao, MD  more...
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Answer

A wide spectrum of disease manifestation has been described, ranging from severe cases presenting as Walker-Warburg syndrome and mild cases presenting as a limb-girdle muscular dystrophy classified as LGMD2K (POMT1) [25] and LGMD2N (POMT2). [26]

Severe cases have structural brain defects similar to those in Walker-Warburg syndrome or muscle-eye-brain disease.

Intermediate patients have congenital muscular dystrophy and mental retardation but no or mild structural brain abnormalities.

In the mildest cases, presentation is with a limb girdle phenotype (LGMD2K or LGMD 2N). Presentation is within the first decade with proximal weakness. The course is slowly progressive. Mild-to-moderate mental retardation is present, while only mild or no structural brain abnormalities have been described.

It appears that most if not all patients with POMT1 mutations have either structural or functional brain disease. This is not true for the mildest cases with mutations in fukutin, FKRP, and POMGnT1 in which mild cases may have no structural or functional brain defects. [22]

In a large cohort of patients from Australia, Turkey, and the United Kingdom with decreased α-dystroglycan staining, mutations in POMT2 (25%) were the most common (cases with mutation in FKRP were excluded). [22] In a large cohort of patients from Italy with CMD and abnormal α-dystroglycan staining, mutations in POMT1 were the most frequent (40%) of the 6 genes involved in glycosylation. [24]


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