Clinical and genetic characteristics of two families with myotonic dystrophy type I / 中华神经医学杂志

ABSTRACT

Objective:To investigate the clinical and genetic characteristics of families with myotonic dystrophy type I.Methods:Two families with myotonic dystrophy type I admitted to Department of Neurology, First Affiliated Hospital of He'nan University of Science and Technology in September and October 2021 were chosen; their clinical data were retrospectively analyzed. The muscle pathological changes were confirmed by electromyography and muscle MRI. Repeat-primed PCR assay was used to detect the number of CTG repeats in the 3' end non-coding region of DMPK gene. Results:Clinical heterogeneity existed among the two families of patients; muscle weakness and muscular atrophy of the skeletal muscle were the main clinical manifestations; limb weakness, axe face, percussion myotonia and myoglobular sign were noted; systemic multi-system symptoms included palpitation and chest tightness, cataracts, gastrointestinal symptoms, fatigue/lethargy, and cognitive impairment. Electromyography showed myotonic potential and myogenic damage. Muscle fatty infiltration and atrophy were noted in muscle MRI, and lesions were predominantly in the gastrocnemius. All patients had abnormal amplification of DMPK gene CTG (number of CTG repeats> 50 or 100). Conclusion:In addition to skeletal muscle involvement, systemic multi-system involvement such as cardiac, eye, respiratory, endocrine, and nervous system should also be noted by clinicians in patients with myotonic dystrophy type I.