Those who recently attended the National LGMD Conference in Chicago learned that the LGMDs are getting new names.
In the old naming system, dominant LGMDs were called LGMD1s and recessive LGMDs were called LGMD2s. The subtypes were further delineated by a letter to designate the gene that contained the disease-causing mutation(s). In the case of CAPN3-mutations, the dominant inheritance form was named LGMD1I and recessive inheritance form was named LGMD2A. This system worked well for a number of years, but ran into trouble recently when the 26th recessive subtype, LGMD2Z, was discovered and the end of the alphabet was reached.
A group of LGMD experts convened to discuss a new strategy of nomenclature, and developed a naming system which includes inheritance (R for recessive, D for dominant), the gene in order of discovery (number), and the name of the affected protein. In the new system, LGMD2A becomes LGMD R1 calpain 3-related, and LGMD1I becomes LGMD D4 calpain 3-related. This article, written by Drs. Madelon Kroneman and Marianne de Visser for the newsletter of Spierziekten Nederland (the Dutch neuromuscular association), gives an explanation of the changes and a full list of the new names.
In the future, we expect that it will become more common for people to use the new nomenclature. For now, C3 will use both old and new nomenclature in our communications, such as “LGMD2A/R1.”