Steinert´s myotonic dystrophy (DM1) is a hereditary disease, characterized by multisystem disorders associated with muscle dysfunction. One of the most frequent clinical manifestations is the myotonic phenomenon (MP), which produces a slowdown of post-isometric muscle relaxation. In this study, the presence of MP in the opening and closing oral movements, movements of the tongue, and other perioral muscles in 50 adult patients with DM1 molecular diagnostics was analyzed. We found MP in 32 of the 50 patients analyzed with DM1 (64%), among which 21 cases (65.6%) were affected with impaired movements of the tongue (highest prevalence), followed by the oral opening movements, which affected 14 patients, and oral closing movements presented in 7 patients. Only 2 patients expressed the symptom of oral opening and closing movements, and in 1 patient, buccinator muscle activity was observed. This study demonstrates that the muscles in the orofacial region are frequently affected in patients with DM1, and hence, the clinician should recognize the MP in these patients.

La distrofia miotónica de Steinert (DM1) es una enfermedad hereditaria, caracterizada por desórdenes multisistémicos asociados a disfunción muscular. Una de las manifestaciones clínicas más frecuentes es el fenómeno miotónico, en el cual se produce un enlentecimiento de la relajación muscular postisométrica. En este estudio analizamos la presencia del fenómeno miotónico (FM) en movimientos de apertura cierre oral, movimientos de la lengua y de otros músculos periorales, en 50 pacientes adultos con diagnóstico molecular de DM1. Nosotros encontramos FM en los movimientos analizados en 32 de los 50 pacientes con DM1 analizados (64%), dentro de los cuales, la mayor prevalencia afectó a los movimientos de la lengua, 21 casos (65,6%), seguidos de los movimientos de apertura oral que afectó a 14 pacientes y de los movimientos de cierre oral que presentó fenómeno miotónico en 7 pacientes. Sólo 2 pacientes expresaron el signo en apertura y cierre oral y en 1 caso se encontró afectada la actividad del músculo buccinador. Este estudio muestra que los músculos de la región orofacial son frecuentemente afectados en los pacientes con DM1, por lo que el clínico debe reconocer el FM en estos pacientes.

As amiotrofias espinhais progressivas (SMAs) constituem as doenças degenerativas de origem genética letais mais comuns do sistema nervoso central e mais freqüentes dentre as doenças autossômicas recessivas após a mucoviscidose. A incidência estimada das SMAs é de aproximadamente 1:10.000 nativivos. Clinicamente, as SMAs são classificadas em mais grave (doença de Werdnig-Hoffmann, tipo I), intermediária (tipo II) e tardia e benigna (doença de Kugelberg-Welander, tipo III). O gene para os três tipos de SMAs foi mapeado no cromossomo 5 q11.2-13.3. Foram identificados dois genes candidatos na mesma região: SMN (sobrevida do neurônio motor) e NAIP (proteína inibidora de apoptose neuronal). Estudamos ambos genes em 87 pacientes brasileiros (20 tipo I,14 tipo II e 53 tipo III) pertencentes a 74 famílias, utilizando as técnicas de PCR e SSCP. Foi encontrada deleção nos exons 7 e/ou 8 do gene SMN em 69% das famílias: 16/20 na tipo I, 9/12 na tipo II e 26/42 na tipo III. Dentre as 51 famílias com deleção, 44 tiveram deleção nos exons 7 e 8 enquanto 7 tiveram deleção somente no exon 7. Deleção no exon 5 do gene NAIP foi encontrada em 7/20 na tipo I, 2/12 na tipo II e 1/42 na tipo III. Não foi encontrada deleção nos genes SMN e NAIP nos 112 progenitores, 26 irmandades assintomáticas e 104 controles normais. Não houve correlação entre deleção de um ou ambos genes com a gravidade do quadro clínico.

Spinal muscular atrophy (SMA), the second most common lethal autosomal recessive disorder, has an incidence of 1:10,000 newborns. SMA is divided into acute (Werdnig-Hoffmann disease, type I), intermediate (type II) and juvenile forms (Kugelberg-Welander disease, type III). The gene of all three forms of SMA maps to chromosome 5q 11.2-13.3. Two candidate genes, the survival motor neuron (SMN) gene and the neuronal apoptosis inhibitory protein (NAIP) gene, have been identified; SMN is deleted in most SMA patients. We studied both genes in 87 Brazilian SMA patients (20 type I, 14 type II and 53 type III) from 74 unrelated families, by using PCR and single strand conformation polymorphism (SSCP). Deletions of exons 7 and/or 8 of the SMN gene were found in 69% of the families: 16/20 in type I, 9/12 in type II and 26/42 in type III. Among 51 families with deletions, 44 had both exons deleted while seven had deletions only of exon 7. Deletions of exon 5 of the NAIP gene were found in 7/20 of type I, 2/12 of type II and 1/42 of type III patients. No deletion of SMN and NAIP genes was found in 112 parents, 26 unaffected sibs and 104 normal controls. No correlation between deletions of one or both genes and phenotype severity was found.