Calpainopathies are a subgroup of limb girdle muscular dystrophies whose symptoms usually appear in early adolescence. In the vast majority of cases, this neuromuscular disease, which affects several hundred people in France, many of them in La Reunion, is transmitted on an autosomal recessive mode. Autosomal dominant forms have been reported in recent years, in very small numbers. Camptocormia is a debilitating posture in which the individual is leaning very forward. Long considered to be a matter of psychiatry, this syndrome is sometimes related to an authentic neuromuscular affection.
In an article published in February 2021, the team at the neuromuscular reference centre in Angers reported, in conjunction with researchers from Généthon, the observation of a 75-year-old person, with no family history, explored for a camptocormic syndrome. seemingly isolated.
Significant degeneration of the paraspinal muscles on MRI imaging led the physicians to continue the aetiological investigations, despite the normal level of CPK and the calpain signal on the Western blot. A mutation in the CAPN3 gene encoding calpain 3 was thus demonstrated in the heterozygous state, suggesting an autosomal dominant inheritance, especially since this same variant had already been involved in a similar observation. The functional studies carried out on a cellular model made it possible to confirm the pathogenic character of the variant.
The authors suggest to evoke more systematically a neuromuscular cause for any late-onset camptocormic syndrome.
