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Updated: Aug 3, 2026

Functional Characterization of Endogenously Expressed Human RYR1 Variants
Published on: June 9, 2021
Familial mydriasis, cardiac arrhythmia, respiratory failure, muscular weakness and hypohidrosis
O Sjaastad1, C F Lindboe, J Schaanning
1Department of Neurology and the Laboratory for the study of autonomic disorders, Trondheim University Hospital, Norway. berit.mjoen@medisin.ntnu.no
Objectives:
To describe a family with some sort of progressive autonomic failure in one generation (2 affected of a sibship of 7 sisters). The main features were: mydriasis, cardiac arrhythmia, cardiomegaly, hypohidrosis, respiratory failure, and muscular weakness.
Methods:
Pupillometry, evaporimetry, and isokinetic power measurements were carried out.
Results:
The autonomic dysfunction pattern (mainly cardiac abnormalities, mydriasis) seems to differ somewhat from that of progressive autonomic failure (Shy-Drager syndrome). "Lewy body-like" inclusions were present, in particular in substantia nigra, but also in locus ceruleus and raphe nuclei (cell loss only in locus ceruleus). There were no oligodendroglial, cytoplasmatic inclusions, apparently a marker in multiple system atrophy. Proper Lewy bodies were also present. Differences seemed to prevail vs the Shy-Drager syndrome. Various traits: muscular weakness pattern (e.g. preferential peroneal distribution), minor elbow contractures, and arrhythmia were reminiscent of Emery-Dreifuss muscle dystrophy (E-D). Distinguishing features included: hereditary pattern, mydriasis, and hypohidrosis.
Conclusion:
Conceivably, this disorder is close to, but still not identical with E-D.
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