[Episodic ataxia type 2: a clinical, genetic and radiological study of 10 patients]. / Ataxia episódica tipo 2: estudio clínico, genético y radiológico de 10 pacientes.

OBJECTIVES: To describe a series of patients with episodic ataxia type 2 (EA2), attending to epidemiological, clinical, radiological, and therapeutic variables. MATERIAL AND METHODS: Retrospective revision of patients with molecular diagnosis of EA2 (CACNA1A mutations), between 1988 and 2022. Information achieved from the database of our Movement Disorders clinic. A descriptive statistical analysis was made. RESULTS: Ten patients from five families were analyzed (six women). Median age at diagnosis was 37.5 years-old, with a median diagnostic delay of 20 years. 70% reported familial history of CACNA1A associated symptoms, although 50% presented migraine, epilepsy, dystonia, or neuropsychiatric alterations. Two heterozygous consanguineous patients had homozygotic descendance with infant mortality due to early-onset epileptic encephalopathy type 42. Five pathogenic/probably pathogenic CACNA1A variants were detected. 80% of patients had episodic triggers, being stress the most common. Episodes had a weekly frequency before treatment initiation. Six patients developed chronic ataxia (one patient demand gait support). 50% of patients with neuroimaging presented cerebellar atrophy. Acetazolamide were initiated in 80%, and 75% of them showed improvement of episodic symptoms. Nephrolithiasis was the most frequent side effect. CONCLUSIONS: EA2 has a great intrafamilial and interfamilial phenotypic variability. The most frequent phenotype were weekly episodes of unsteadiness, several hours of length, stress as the main trigger, chronic ataxia and gaze-evoked nystagmus. Acetazolamide is effective, although complications are usual. Neurologist must be alert as diagnostic delay is constant.

TITLE: Ataxia episódica tipo 2: estudio clínico, genético y radiológico de 10 pacientes.Objetivo. Describir una serie de pacientes con ataxia episódica tipo 2 (AE2) según variables epidemiológicas, clínicas, radiológicas y terapéuticas. Material y métodos. Revisión retrospectiva de pacientes con diagnóstico molecular de AE2 (mutación en CACNA1A) entre 1988 y 2022, información recogida de la base de datos de la Unidad de Trastornos del Movimiento de nuestro centro. Se realizó un análisis estadístico descriptivo. Resultados. Se analizó a 10 pacientes procedentes de cinco familias. La mediana de edad en el momento del diagnóstico fue 37,5 años, con un retraso diagnóstico de 20 años. El 50% asociaba epilepsia, migraña, distonía o alteraciones neuropsiquiátricas. El 70% tenía una historia familiar de síntomas asociados a CACNA1A. Dos pacientes heterocigotos consanguíneos tuvieron descendencia homocigota con mortalidad infantil por encefalopatía epiléptica de inicio precoz de tipo 42. Se detectaron cinco variantes diferentes de CACNA1A. El 80% mostró factores desencadenantes, y el estrés fue el más común. La frecuencia episódica más habitual fue semanal. Seis pacientes desarrollaron ataxia interepisódica, aunque sólo uno precisó apoyo en la marcha. El 50% de los pacientes con neuroimagen presentó atrofia cerebelosa. El 80% inició acetazolamida durante el seguimiento, con respuesta a dosis altas en el 75%. La nefrolitiasis fue el efecto adverso más frecuente. La 4-aminopiridina fue una alternativa eficaz. Conclusiones. La AE2 presenta una alta variabilidad fenotípica inter- e intrafamiliar. El fenotipo más frecuente fueron episodios de inestabilidad, de horas de duración, semanales, con estrés como desencadenante, ataxia persistente y nistagmo evocado por la mirada. La acetazolamida, aunque es eficaz, no está exenta de complicaciones. El retraso diagnóstico es muy frecuente.

Biallelic variants in genes previously associated with dominant inheritance: CACNA1A, RET and SLC20A2.

A subset of families with co-dominant or recessive inheritance has been described in several genes previously associated with dominant inheritance. Those recessive families displayed similar, more severe, or even completely different phenotypes to their dominant counterparts. We report the first patients harboring homozygous disease-related variants in three genes that were previously associated with dominant inheritance: a loss-of-function variant in the CACNA1A gene and two missense variants in the RET and SLC20A2 genes, respectively. All patients presented with a more severe clinical phenotype than the corresponding typical dominant form. We suggest that co-dominant or recessive inheritance for these three genes could explain the phenotypic differences from those documented in their cognate dominant phenotypes. Our results reinforce that geneticists should be aware of the possible different forms of inheritance in genes when WES variant interpretation is performed. We also evidence the need to refine phenotypes and inheritance patterns associated with genes in order to avoid failures during WES analysis and thus, raising the WES diagnostic capacity in the benefit of patients.

The high prevalence of impulse control behaviors in patients with early-onset Parkinson's disease: A cross-sectional multicenter study.

INTRODUCTION: In Parkinson's disease patients, impulse control disorders (ICDs) have been associated with younger age and early disease onset, yet the prevalence of ICDs in early-onset Parkinson's disease (EOPD) patients has yet to be studied. Thus, we set out to compare the prevalence of impulse control behaviors (ICBs) in a cohort of EOPD patients with that in age and gender matched healthy controls (HCs), as well as to analyze the association of these symptoms with the use of dopaminergic drugs and other clinical or demographic factors. METHODS: A cross-sectional, multicenter study was carried out on patients recruited from outpatient Movement Disorder Clinics, assessing ICBs using the short form of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP). In addition, depression and quality of life (QoL) were measured, along with other demographic and clinical variables. RESULTS: Of the 87 EOPD patients, 49 (58.3%) displayed an ICB, as did 28 of the 87 HCs (32.9%; p=0.001). Most of the EOPD patients that displayed an ICB (91.8%) were medicated with a dopamine agonist (DA) and accordingly, DA treatment was associated with a 7-fold increased risk of developing an ICB. Patients with ICBs had a higher depression score and a worse QoL. CONCLUSIONS: ICBs are much more prevalent in EOPD patients than in HCs and they are associated with DA intake, depression and a worse QoL.

[Cardiac involvement in neuromuscular diseases]. / Repercusión cardíaca de las enfermedades neuromusculares.

Many neuromuscular disorders involve the heart, occasionally with overt clinical disease. Muscular dystrophies (dystrophinopathies, limb girdle muscular dystrophy, Emery-Dreifuss muscular dystrophy, Steinert's myotonic dystrophy), congenital myopathies, inflammatory myopathies and metabolic diseases (glycogenosis, periodic paralysis, mitochondrial diseases) may produce dilated or hypertrophic cardiomyopathy and heart rhythm or conduction disturbances. Furthermore the heart is commonly involved in some hereditary and degenerative diseases (Friedreich's ataxia and Kugelberg-Welander syndrome) and acquired (Guillain-Barré syndrome) or inherited (Refsum's disease and Charcot-Marie-Tooth syndrome) polyneuropathies. A cardiologist's high clinical suspicion and a simple but systematic skeletal muscle and peripheral nerve investigation, including muscle enzymes quantification, neurophysiological study and muscle biopsy, are necessary for an accurate diagnosis. In selected patients, more sophisticated biochemical and genetic analysis will be necessary. In most cases, endomyocardial biopsy is not essential for the diagnosis.