LGMD manual

1.7. What is the progression of LGMD?
In this regard, the Muscular Dystrophy Association 1 comments as follows:
At this time, progression in each type of LGMD cannot be predicted with certainty, although
knowing the underlying genetic mutation can be helpful. Some forms of the disorder progress to
loss of walking ability within a few years and cause serious disability, while others progress very
slowly over many years and cause minimal disability.
LGMD can begin in childhood, adolescence, young adulthood, or even later. Both genders are
affected equally.
When LGMD begins in childhood, some physicians say, the progression is usually faster and the
disease more disabling. When the disorder begins in adolescence or adulthood, they say, it is
generally not as severe and progresses more slowly. The course is usually one of slowly
progressive, mostly symmetric weakness, with the exception of a few types with rapid
progression or asymmetric weakness.
1.8. Subtypes of LGMD
According to the Muscular Dystrophy Association 1 LGMD can be divided into subtypes.
Type 1 LGMDs are dominantly inherited, requiring only one mutation for symptoms to result.
Type 2 LGMDs are recessively inherited, requiring two mutations, one from each parent for
symptoms to appear. Sometimes, LGMDs are referred to by their names, not their numbers, and
some types have not been assigned numbers. The discovery of genetically distinct subtypes has
redefined the classification of LGMD and has led to nomenclature designating the autosomal
dominant forms as LGMD1A, 1B, 1C, etc., and the autosomal recessive forms as LGMD2A, 2B, 2C,
etc.”
Furthermore, Muscular Dystrophy UK 3 states: “The different types of LGMD may have different
features associated with them *…+. However, the common features to all people in this group will
be weakness of the big muscles of the legs and/or arms.”
The table below lists the LGMD subtypes and specifies the autosomal dominant and autosomal recessive
types. 4 Name Old name Name Old name
LGMD D1 DNAJB6-
related
LGMD D2 TNP03-
related
LGMD D3 HNRNPDLrelated
LGMD D4 calpain3-
related
LGMD D5 collagen6-
related
LGMD R1 calpain3-
related
AUTOSOMAL DOMINANT
LGMD1D
LGMD R12 anoctamin5-
related
LGMD1F
LGMD R13 Fukutinrelated
LGMD1G
LGMD R14 POMT2-
related
LGMD1I
LGMD R15 POMGnT1-
related
Bethlem
LGMD R16 α-
myopathy dominant dystroglycan-related
AUTOSOMAL RECESSIVE
LGMD2A
LGMD R17 plectinrelated
LGMD2L
LGMD2M
LGMD2N
LGMD2O
LGMD2P
LGMD2Q
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