Postural Instability in Prodromal Spinocerebellar Ataxia Type 2: Insights into Cerebellar Involvement Before Onset of Permanent Ataxia

Studies on prodromal stage in spinocerebellar ataxias (SCAs) have become high priority approaches in view of their usefulness to detect biomarkers that herald the onset of permanent ataxia and assess the efficacy of future therapeutical trials [1]. The most comprehensive evaluation of prodromal SCA2 comes from the large and homogeneous population of Cuban preclinical carriers, which derives from a 13 years presymptomatic diagnostic program and the nationwide molecular epidemiological survey (AU)

Couples at risk for spinocerebellar ataxia type 2: the Cuban prenatal diagnosis experience

Cuba reports the highest worldwide prevalence of spinocerebellar ataxia type 2 (SCA2) and the greatest number of descendants at risk. A protocol for genetic counseling, presymptomatic testing, and prenatal diagnosis of hereditary ataxias has been under development since 2001. Considering that the revision of the experience with prenatal diagnosis for SCA2 in Cuba would enable comparison of ours with international findings, we designed a descriptive study, based on the retrospective revision of the medical records belonging to the 58 couples that requested their inclusion in the program, during an 11-year period (2001-2011). Most of the participants in the prenatal diagnosis program were known presymptomatic carriers, diagnosed through the presymptomatic testing in the same period of study, for an uptake among them of 22.87 percent (51 out of 223). In 28 cases, the fetuses were carriers, 20 of these couples (71.43 percent) decided to terminate the pregnancy; the rest continued the pregnancy to term, this resulting in a predictive test for their unborn children. A predominance of females as the at-risk progenitor was observed. Except for a slightly lower average age, the results attained in the Cuban SCA2 prenatal diagnosis program resulted similar to the ones reported for Huntington disease in other countries. It is necessary to have easy access to the Cuban program through its expansion to other genetic centers along the island. Future research is needed to evaluate the long-term impact of both the predictive testing in unborn children and the selection of other reproductive options by the at-risk couples (AU)

Age dependent risks in genetic counselingfor spinocerebellar ataxia type 2

Spinocerebellar ataxia type 2 (SCA2, OMI health, reproductive, financial matters, and183090) belongs to a group of hereditary family planning. Therefore, we undertook a sur-neurodegenerative diseases caused by the expan- vey of the age of onset in a cohort of SCA2sion of a CAG repeat tract in coding regions of patinovel genes. This group includes Huntingtonsdisease (HD), spinal and bulbar muscularatrophy (SBMA), dentatorubral-pallidoluysianatrophy, and the spinocerebellar ataxias type 1,3, 6, 7, and 17 (1). These mutations show a veryhigh penetrance, and they follow an autosomaldominant inheritance pattern with the onlyexception of SBMA (X-linked); each descendantof an affected patient has an a priori risk of 50%.However, it has been proven that the empiric riskof having inherited the mutation causing HD orSCA3 (Machado–Joseph disease) lessens withadvancing age (2, 3). This fact has significantimplications in the genetic counseling of at-riskindividuals. The accuracy and precision that areachieved in the estimate of the risk of developinga certain hereditary illness will have a very...(AU)

Conducción nerviosa del facial: relación con el tipo de cara / Facial nervous conduction relation with the face type

Los estudios neurofisiológicos, y entre ellos los de conducción nerviosa motora, suelen ser de gran importanciapor brindar información de gran valor diagnóstico en diferentes patologías como la ataxia espinocerebelosa tipo2, la forma más frecuente en nuestro país, y particularmente en Holguín, y cuya prevalencia es considerada una de lasmás altas del mundo. El propósito del presente trabajo es determinar la posible relación entre la conducción nerviosamotora del nervio facial y el tipo de cara. Pacientes y métodos: Para ello fueron estudiados 101 pacientes con diagnósticoclínico y molecular de ataxia espinocerebelosa tipo 2 (SCA 2) y 36 descendientes presintomáticos. En cada caso serealizaron estudios moleculares, examen bucal, medición de la cara y determinación del tipo facial, previo estudio deconducción nerviosa motora del facial (VII par craneal). Resultados: Éstos mostraron una prolongación de la latencia delpotencial en los enfermos y de la duración tanto en los sujetos enfermos como en los portadores asintomáticos encomparación con el patrón referencial creado en un grupo de sujetos sanos y la no-existencia de relación alguna entre eltipo facial y los parámetros mesurables de la conducción nerviosa del VII par craneal. Conclusiones: La prolongación delos valores de latencia y duración del potencial motor son expresión de la existencia de una lesión de tipo mielínica dedicho par craneal tanto en los enfermos como en los descendientes portadores de la mutación SCA 2.Palabras clave: conducción nerviosa del facial, biotipología facial, tipos de cara, latencia motora distal del facial, ataxiaespinocerebelosa tipo 2, ataxia cerebelosa cubana...(AU)

Neurophysiological studies and particularly motor nerve conduction studies are very important becausethey give us certain diagnostic information of different pathologies including Spinocerebellar Ataxia Type 2, the mostfrequent form in Cuba and in Holguín, whose prevalence is considered as one of the highest in the world. The purpose ofthis study is in order to determine the relationship between motor conduction parameters of facial nerve and facialtypes. Patients and methods: We studied 101 patients with clinical and molecular diagnosis of SCA 2 and 36presimptomatic relatives. In all cases were made molecular studies, oral exam and face measurements to determingfacial type after a previous facial nerve motor conduction study of VII cranial pair. Results: These showed a latencyprolongation of the potential in patients and of the duration both in SCA 2 patients as its relatives in comparison withhealthy subjects and in the asymptomatic bearers as compared to the reference pattern (control group of healthysubjects), and the non-existing relationship between facial type and motor nerve conduction parameters. Conclusions:The facial nerve in SCA 2 patients and their relatives. Theres a positive proof...(AU)