RESUMEN
Episodic ataxia type 1 and 2 (EA1 and EA2) are the most well-described of the episodic ataxias. They are autosomal dominantly inherited early-onset diseases characterized by attacks of cerebellar dysfunction. EA1 is clinically characterized by short episodes of ataxia with interictal myokymia, whereas EA2 is characterized by longer-lasting recurrent ataxia, slurred speech, and interictal nystagmus. We report on a patient with EA2 with interictal focal dystonia and also interictal myokymia, which is hitherto not reported as an interictal feature associated to EA2. The patient carries a previously described heterozygous pathogenic de novo frameshift variant in the CACNA1A gene, establishing the diagnosis of EA2. She had symptom onset at age 13 and from age 48 she developed interictal myokymia and focal dystonia as illustrated in Supplemental Movie S1. We conclude that interictal myokymia and focal dystonia may be interictal features associated to EA2 caused by the cerebellar pathophysiology of EA2. Episodes of ataxia were successfully treated with acetazolamide in low dose, whereas the interictal features were unresponsive to acetazolamide.
Asunto(s)
Ataxia Cerebelosa , Trastornos Distónicos , Miocimia , Femenino , Humanos , Adolescente , Persona de Mediana Edad , Acetazolamida , Miocimia/diagnóstico , Miocimia/genética , Canales de Calcio/genética , Ataxia/diagnóstico , Ataxia/genética , Ataxia Cerebelosa/genética , Trastornos Distónicos/diagnóstico , Trastornos Distónicos/genéticaRESUMEN
Mutations of the main voltage-gated K channel members Kv1.1 are linked to several clinical conditions, such as periodic ataxia type 1, myokymia and seizure disorders. Due to their role in active magnesium reabsorption through the renal distal convoluted tubule segment, mutations in the KCNA1 gene encoding for Kv1.1 has been associated with hypomagnesemia with myokymia and tetanic crises. Here we describe a case of a young female patient who came to our attention for a history of muscular spasms, tetanic episodes and muscle weakness, initially misdiagnosed for fibromyalgia. After a genetic screening she was found to be carrier of the c.736A > G (p.Asn255Asp) mutation in KCNA1, previously described in a family with autosomal dominant hypomagnesemia with muscular spasms, myokymia and tetanic episodes. However, our patient has always presented normal serum and urinary magnesium values, whereas she was affected by hypocalcemia. Calcium supplementation gave only partial clinical benefit, with an improvement on tetanic episodes yet without a clinical remission of her spasms, whereas magnesium supplementation worsened her muscular symptomatology.
Asunto(s)
Calcio/administración & dosificación , Hipocalcemia , Canal de Potasio Kv.1.1/genética , Magnesio/sangre , Miocimia , Tetania , Adulto , Encéfalo/diagnóstico por imagen , Hormonas y Agentes Reguladores de Calcio/administración & dosificación , Diagnóstico Diferencial , Femenino , Humanos , Hipocalcemia/diagnóstico , Hipocalcemia/etiología , Hipocalcemia/terapia , Imagen por Resonancia Magnética/métodos , Mutación , Miocimia/diagnóstico , Miocimia/tratamiento farmacológico , Miocimia/genética , Miocimia/fisiopatología , Examen Neurológico/métodos , Tetania/diagnóstico , Tetania/tratamiento farmacológico , Tetania/genética , Tetania/fisiopatologíaRESUMEN
Peripherally induced movement disorders are relatively rare. Here, we present 3 patients who suffered a lesion of the brachial plexus because of neuralgic amyotrophy and developed involuntary movements of their shoulder muscles. The nature of the involuntary movements, which did not easily comply with classic descriptions of hyperkinetic movement disorders, is probably best referred to as dystonia.