Form of congenital myopathy characterized by the presence of tubular aggregates derived from the sarcoplasmic reticulum in 60-90 % of the muscle fibers. There is also a predominance of type I fibers with atrophy of type II fibers. It presents as progressive muscle weakness starting in adulthood without myalgia, cramps or amyotrophy.

Two types are described:

-        type 1 [MIM 160 565]: autosomal dominant transmission of a mutation of the STIM1 gene (11p15.4), also present in the Stormorken syndome (see this term); Normal CPK levels

-        type 2 [MIM 615 883]: autosomal dominant transmission of a mutation of the ORAI1 gene (12q24); there are ocular abnormalities (myosis), lower limb areflexia and the CPK levels are elevated

Anesthetic implications:

avoid succinylcholine; risk of malignant hyperthermia ?

References :

-        Benarroch L, Bonne G, Rivier F, Hamroun D.
The 2020 version of the gene table of neuromuscular disorders.
Neuromusc Dis 2019 ; 29 : 980-1018 ou http://www.musclegenetable.fr.

Updated: June 2021