GTR Home > Conditions/Phenotypes > Congenital muscular dystrophy-dystroglycanopathy with mental retardation, type B6


Excerpted from the GeneReview: Congenital Muscular Dystrophy Overview
Congenital muscular dystrophy (CMD) is a clinically and genetically heterogeneous group of inherited muscle disorders. Muscle weakness typically presents from birth to early infancy. Affected infants typically appear "floppy" with low muscle tone and poor spontaneous movements. Affected children may present with delay or arrest of gross motor development together with joint and/or spinal rigidity. Muscle weakness may improve, worsen, or stabilize in the short term; however, with time progressive weakness and joint contractures, spinal deformities, and respiratory compromise may affect quality of life and life span. The main CMD subtypes, grouped by involved protein function and gene in which causative allelic variants occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutation of POMT1, POMT2, FKTN, FKRP, LARGE1, POMGNT1, and ISPD), SELENON (SEPN1)-related CMD (previously known as rigid spine syndrome, RSMD1) and LMNA-related CMD (L-CMD). Several less known CMD subtypes have been reported in a limited number of individuals. Cognitive impairment ranging from intellectual disability to mild cognitive delay, structural brain and/or eye abnormalities, and seizures are found almost exclusively in the dystroglycanopathies while white matter abnormalities without major cognitive involvement tend to be seen in the laminin alpha-2-deficient subtype.

Available tests

42 tests are in the database for this condition.

Genes See tests for all associated and related genes

  • Also known as: LARGE, MDC1D, MDDGA6, MDDGB6, LARGE1
    Summary: LARGE xylosyl- and glucuronyltransferase 1

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