RESUMEN
We report a patient with early onset facioscapulohumeral muscular dystrophy type 1 (FSHD1) who was not diagnosed until 48 years of age. She developed progressive facial diplegia from the age of 4-5 years followed by limb muscle weakness. Motor nerve conduction was normal, myopathic changes were seen electromyographically. Creatine kinase activity was mildly increased at the beginning. Muscle biopsy at 8 years suggested a neurogenic pattern, a second biopsy at age 30 was chronic myopathic with fibre calibre variation. The patient lost the ability to walk at age 44. When last seen she had total facial diplegia, no active movements in her limbs, mild kyphoscoliosis and a rigid thoracic spine. Molecular studies revealed a shortened D4Z4 fragment confirming the diagnosis FSHD1. Her family history was unremarkable, suggesting a de novo mutation. This report is to illustrate the evolving phenotype of early onset FSHD1 with predominating facial palsy.
Asunto(s)
Parálisis Facial/complicaciones , Parálisis Facial/diagnóstico , Distrofia Muscular Facioescapulohumeral/complicaciones , Distrofia Muscular Facioescapulohumeral/diagnóstico , Edad de Inicio , Diagnóstico Diferencial , Parálisis Facial/genética , Parálisis Facial/fisiopatología , Femenino , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Distrofia Muscular Facioescapulohumeral/genética , Distrofia Muscular Facioescapulohumeral/fisiopatología , FenotipoAsunto(s)
Secuenciación de Nucleótidos de Alto Rendimiento , Enfermedades Musculares/diagnóstico , Enfermedades Musculares/genética , Adolescente , Niño , Preescolar , Asesoramiento Genético , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Hallazgos Incidentales , Lactante , Recién Nacido , Enfermedades Musculares/congénitoRESUMEN
The Duchenne Muscular dystrophy (DMD) is the most frequent muscle disorder in childhood caused by mutations in the Xlinked dystrophin gene (about 65% deletions, about 7% duplications, about 26% point mutations and about 2% unknown mutations). The clinically milder Becker muscular dystrophy (BMD) is allelic to DMD. About 33% of all patients are due to de novo mutations and germ line mosaicism is frequently observed. While in earlier studies equal mutation rates in males and females had been reported, a breakdown by mutation types can better explain the sex ratio of mutations: Point mutations and duplications arise preferentially during spermatogenesis whereas deletions mostly arise in oogenesis. With current analytical methods, the underlying mutation can be identified in the great majority of cases and be used for carrier detection. However, in families with no mutation carrier available, the genetic model to be used for counselling of relatives can be quite complex.
Asunto(s)
Distrofia Muscular de Duchenne/genética , Consejo , Tamización de Portadores Genéticos , Humanos , Distrofia Muscular de Duchenne/diagnóstico , Mutación , Linaje , Medición de RiesgoRESUMEN
Several subtypes of facioscapulohumeral muscular dystrophy (FSHD) with atypical clinical presentation have been described. We report a new, distinct phenotype with progressive bent spine syndrome solely affecting the paraspinal muscles. Magnetic resonance imaging study of the lumbar spine revealed marked atrophy of the paraspinal muscles. The diagnosis was confirmed by DNA testing, which revealed shortened restriction fragments of the D4Z4 repeat on haplotype A in connection with a positive family history.
Asunto(s)
Atrofia Muscular Espinal/complicaciones , Distrofia Muscular Facioescapulohumeral/complicaciones , Curvaturas de la Columna Vertebral/complicaciones , Anciano , Haplotipos , Humanos , Dolor de la Región Lumbar/complicaciones , Dolor de la Región Lumbar/genética , Masculino , Atrofia Muscular Espinal/genética , Distrofia Muscular Facioescapulohumeral/genética , Linaje , Curvaturas de la Columna Vertebral/genéticaRESUMEN
Previous family studies revealed a large number of calpain 3 ( CAPN3 ) mutations that cause recessive forms of limb girdle muscular dystrophy (LGMD2A) with selective atrophy of the proximal limb muscles. Correlations between the nature and site of a particular mutation and its corresponding phenotype, however, can only be established from homozygous mutations, which are particularly rare in the alternatively spliced NS, IS1 and IS2 regions of CAPN3. Here we identified a sibling pair with LGMD2A-type muscular dystrophy caused by a homozygous Ser606Leu (S606L) substitution in the IS2 linker domain. Normal protein levels, unaltered myofibrillar targeting and conserved calcium-induced autocatalytic activity of the mutated protein could be demonstrated in muscle biopsies from one patient. Despite this inconspicuous modification of the IS2 linker between domains III and IV, both patients developed signs and symptoms of the disease within their second decade of life. The unexpected severity of the clinical manifestation points to the high relevance of the calpain 3-specific IS2 segment between domains III and IV. We conclude that the structural motif around the Ser606 residue represents an important functional site that may regulate the transient activation and limited proteolysis of calpain 3.
Asunto(s)
Empalme Alternativo , Calpaína/genética , Isoenzimas/genética , Proteínas Musculares/genética , Distrofia Muscular de Cinturas/genética , Mutación , Edad de Inicio , Secuencias de Aminoácidos/genética , Sustitución de Aminoácidos , Mapeo Cromosómico , Análisis Mutacional de ADN/métodos , Exones , Variación Genética , Homocigoto , Humanos , Modelos Moleculares , Distrofia Muscular de Cinturas/patología , Distrofia Muscular de Cinturas/fisiopatología , Linaje , Conformación Proteica , Estructura Terciaria de Proteína , HermanosRESUMEN
Cardiac involvement (CI) in form of myocardial thickening in a patient with genetically confirmed facioscapulohumeral muscular dystrophy (FSHMD) has not been reported. The patient is a 50-year-old male with a tandem repeat size of 17 and 14 kb in the D4Z4 locus on chromosome 4q35. The clinical cardiologic investigation was normal. Blood pressure was 150/90 mm Hg. Funduscopy, 24-hour ambulatory ECG, and 24-hour blood pressure monitoring were normal. ECG showed incomplete right bundle branch block, ST elevation in V2-V4, tall T waves in V3-V5, and hypertrophy signs. Echocardiography revealed left ventricular myocardial thickening of the posterior wall (11.7 mm) and the septum (15.5 mm). In conclusion, CI in genetically confirmed FSHMD may manifest not only as ECG abnormalities but also as left ventricular myocardial thickening.