Case Report
Volume 12 Issue 12 - 2020
Lid Lag Phenomenon Revealing Myotonia Congenita: Case Report
Musa Juna1*, Compres L2, Rosario M3, Hyseni F4, Rahman M5, Rakovica L6, Saliaj K7, Guy A8, Kola I9 and Blanco R10
1Department of Surgery Physiology and Biomedical Engineering Mayo Clinic, Rochester, Minnesota, USA
2Neurology Department Fellows, University of Cincinnati Medical Center, USA
3Neurology Department, Clinica Bonilla, Santiago Dominican Republic
4Department of Urology, NYU Langone Health, New York, USA
5Department of Neurosurgery, Mayo Clinic, Rochester, MN, USA
6University of Prishtina, Faculty of Medicine, Prishtina, Kosovo
7University of Medicine, Faculty of Medicine, Tirana, Albania
8Clinical Assistant Professor, Department of Physical Medicine and Rehabilitation, New York University School of Medicine, NYU Medical Center, New York, USA
9Department of Burns and Plastic Surgery, University Hospital Center “Mother Teresa”, Tirana, Albania
10Centro de Diagnóstico Por Imágenes Clínico Integral (CEDICLIN), Santiago, Dominican Republic
*Corresponding Author: Juna M, Department of Surgery Physiology and Biomedical Engineering Mayo Clinic, Rochester, Minnesota, USA.
Received: October 15, 2020; Published: November 26, 2020


Myotonic disorders represent rare, genetically heterogeneous neuromuscular diseases, whose clinical hallmark is the presence of myotonia. Myotonic disorders are generally classified as either dystrophic (DM) or non-dystrophic myotonia (NDM). Non-dystrophic myotonias (NDM) are skeletal muscle channelopathies characterized by a disruption of normal sarcolemmal ion conductance that results in abnormal muscle fiber excitability. Depending on the affected ion channels, non-dystrophic myotonias include myotonia congenita (MC), paramyotonia congenita (PMC) and sodium channel myotonia (SCM).

Myotonia congenita (MC) is the most common type of non-dystrophic myotonia, occurring due to mutations in CLCN1, the gene encoding the primary skeletal muscle voltage-gated chloride channel (ClC-1). Diagnosis is suspected in the setting of myotonia, muscular stiffness, the warm-up phenomenon, family history and electromyographic studies suggestive of myotonia congenita and is ultimately established through genetic testing.

In this case report, we present a 9-year-old male patient with complaints of muscular stiffness, difficulty in climbing stairs, with calf and buttock hypertrophy and percussion myotonia in both hands and calves evident in physical examination. A diagnosis Myotonia Congenita was made based on the presence of a positive Lid lag sign, a positive warm up test and the results of electromyography (EMG) studies. It was then confirmed by genetic testing.

Along with showcasing a rare pathology, this case report emphasises the importance of a thorough clinical evaluation and electrophysiological studies as the best initial assessments of myotonia, when considering the differential diagnosis and in guiding appropriate genetic testing.

Keywords: Non-Dystrophic Myotonia; Channelopathies; Myotonia Congenita; Electrophysiology


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Citation: Musa Juna., et al. “Lid Lag Phenomenon Revealing Myotonia Congenita: Case Report”. EC Neurology 12.12 (2020): 28-35.

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