Congenital muscular dystrophy-dystroglycanopathy with mental retardation type B1

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Classification according to ICD-10
G71.2 Congenital myopathies
ICD-10 online (WHO version 2019)

The congenital muscular dystrophy Dystroglykanopathie with mental retardation type B1 (engl. Congenital muscular dystrophy-dystroglycanopathy with mental retardation type B1 , short MDDGB1 ) is a hereditary muscular disease belonging to the group of congenital muscular dystrophies belongs.

The disease is very rare; only a few cases are described in the specialist literature. The cause is a mutation in the POMT1 gene , whose gene product is the glycosyl transferase POMT1 . The result is reduced glycosylation of the protein α-dystroglycan . As a component of the dystrophin / dystroglycan complex , α-dystroglycan plays an important role in the stability of the cell membrane of muscle and nerve cells. Diseases that lead to disorders of the glycosylation of α-dystroglycan are also known as dystroglycanopathies . MDDGB1 is inherited as an autosomal recessive trait. So-called compound heterozygous mutations in the POMT1 gene could be detected in a total of 3 patients .

Mutations in the POMT1 gene can also lead to dystroglycanopathies with a different phenotype: These include the POMT1-associated Walker-Warburg syndrome and the POMT1-associated muscle-eye-brain disease with a more severe course, as well as the milder girdle dystrophy LGMD2K .

Clinical manifestations

The MDDGB1 is characterized by muscle weakness, which usually begins before the ability to walk is acquired. The muscle weakness can be accompanied by mental retardation and slight malformations of the brain, but these are less pronounced than is the case with Walker-Warburg syndrome and muscle-eye-brain disease. Neuronal migration disorders do not occur.

Individual evidence

  1. ↑ a b c MDDGB1.  In: Online Mendelian Inheritance in Man . (English)
  2. ↑ J. van Reeuwijk, S. Maugenre u. a .: The expanding phenotype of POMT1 mutations: from Walker-Warburg syndrome to congenital muscular dystrophy, microcephaly, and mental retardation. In: Human mutation Volume 27, Number 5, May 2006, pp. 453-459, ISSN  1098-1004 . doi : 10.1002 / humu.20313 . PMID 16575835 .