Isochromosome X mosaicism in a child with Kabuki syndrome phenotype: A rare cytogenetic association.

Isochromosome is a structurally unbalanced chromosome consisting of two short arms or two long arms, which are derived by abnormal centromere division or sister-chromatid exchange. Most autosomal isochromosomes are unusual, while those involving sex chromosomes are common. Kabuki syndrome (KS, OMIM 147920) is a multiple malformation/mental retardation syndrome of unknown etiology. A conventional cytogenetic study on lymphocytes from a 4-year-old girl with physical features suggestive of KS was found to have mosaicism for isochromosome for the long arm of the X. Although most manifestations present in this patient have been described before, this report is a rare association of clinical and cytogenetic findings in this syndrome. A genome-wide analysis and a larger number of patient groups studied could improve our understanding of the genetic basis of KS.

Turner syndrome: Cardiovascular abnormalities and correlation with clinical phenotype and karyotype

Turner Syndrome [TS] is the most common sex chromosomal abnormality. Patients [Pts] with TS are known to have higher incidence of congenital heart disease [CHD] than the general population. No studies have reported echocardiographic data according to the phenotype and chromosomal pattern in our country. The aim of our study was to assess an institutional experience. During 1995 to 2002, 37 unselected Pts with TS underwent cardiologic evaluation at the Imam-Reza Hospital. Karyotype distribution was: 45,X [65%], X-structural abnormalities [30%] and X-mosaism [5%].The mean age at the time of diagnosis was 12.81 +/- 4.48 years. The prevalence of CHD was 21%. Coarctation of Aorta [CoA] was the most prevalent CHD. [Absolute and relative risk was 16% and 75% respectively] The Pts with 45, X karyotype had the greatest prevalence of CHD, and the PTS with X-mosaism showed no signs of CHD. The PTS with severe dysmorphic signs had 45, X karyotype and showed a significant higer relative risk of cardiac malformations. There is an absolute higher prevalence of CHD in Pts with TS. An accurate, periodic cardiologic evaluation is necessary in all Pts with TS.

Dental management of patients suffering from [Lowe syndrome]

Lowe syndrome [LS] is an x-linked recessive disorder of unknown etiology resulting in ocular, cerebral and renal disorder. It is X linked recessive disorder, caused by a defective gene on Chromosome number Xq 26. Males are more affected than females. Clinical features are bilateral congenital cataract [100%], Glaucoma, Infantile hypotonia, gross motor developmental delay, reduced or absent deep tendon reflexes, muscle wasting, moderate to severe mental retardation, frequent high pitched scream seizures, growth failure, Rickets, Joint hyper mobility and renal manifestations. Prognosis is poor for normal life style. There are developmental delays, visual problems and progressive mental retardation. The patient dies in the first decade of complication of Fanconi syndrome if treatment is not provided. Lifespan can be extended with supportive therapy. A case of LS with dental management, although not ideal is presented. Mentally retarded patients needs regular dental visits to reduce avoidable dental pain

Estudo retrospectivo de 72 casos de genitália ambígua / A retrospective study of 72 cases of ambiguous genitalia

Foram avaliados, retrospectivamente, 72 casos de genitália ambígua encaminhados para estudo citogenético ao Serviço de Genética da Fundaçäo Faculdade Federal de Ciências Médicas de Porto Alegre, entre 1975 e 1989. Procurou-se avaliar em que idade é feito o diagnóstico clínico, quais as anomalias cromossômicas apresentadas e quais os diagnósticos mais freqüêntes. Observou-se que um número expressivo de pacientes foi avaliado citogenética, havia mosaicismo dos cromossomos sexuais, com linhagens celulares apresentando cromossomo Y, o que representa risco de neoplasia gondal. Os diagnósticos mais freqüentes foram hiperplasia supra-renal congênita virilizante e feminizaçäo testicular incompleta. Concluímos que o diagnóstico clínico deve ser estabelecido o mais precoemente possível, e que o estudo citogenético deve ser realizado em todos os pacientes que apresentam genitália ambígua

Tamizaje de sitio frágil en el cromosoma X en una población de retardados mentales: hallazgos preliminares / Screening for the X chromosome fragile site in a mentally retarded population

El sitio frágil del cromosoma X es la anomalía cromosómica más común, después de la trosomía 21, entre varones con retardo mental de etiología genética, y además se asocia con deficiencia mental en más de la mitad de los casos de mujeres portadoras. Este estudio en el primer intento de averiguar sis sucede esto mismo en nuestro país, en una muestra de retardados mentales seleccionados. El tamizaje se está realizado en la Escuela de Eseñanza Especial "Fernando Centeno Güel" mediante análisis cromosómico de un mínimno de 100 figuras mitóticas de cada individuo, obtenidas del cultivo por 92 horas, de sangre periférica en medio 199 suplementado al 5% con suero fetal bovino. Los resultados preliminares obtenidos confirman la presencia de este marcador cromosómico también entre nuestros retardados mentales y con una frecuencia (5%) similar a la informada en la literatura. Las implicaciones concomitantes al diagnóstico del síndrome del X frágil son muy importantes en varios aspectos: la asesoría genética adecuada y oportuna podría prevenir en muchos casos la concepción de individuos afectados, el tratamiento con ácido fólico parece promisorio y por último, existe la opción del diagnóstico fetal y prevención post-concepción

X/15 translocation in a mentally normal XXX woman

Foi verificada, em cultura de sangue periférico, de pacientes enviada para Aconselhamento Genético, trissomia do cromossomo X, acompanhada de uma translocaçäo entre o X extra e um dos cromossomos 15. A paciente, mentalmente normal, apresentou problema congênito de má formaçäo óssea nos membros inferores (corrigido cirurgicamente, ainda na infância) e problemas de abortos e esterilidade secundária por ciclo anovulatóro. Ma formaçäo óssea foi também encontrada em irmäo, primo e sobrinho, carotipicamente normais, do propósito. O exame da família do propósito revelou ser a mäe da paciente portadora de mosaicismo 46,XX/47,XXX/48,XXXX, com predominância de linhagem 47,XXX. Foram empregadas técnicas de bandeamento G, autorradiografia, cromatina sexual e baqueta, para estudo das anomalias em questäo , discutindo-se o comportamento de marcaçäo tardia dos cromossomos envolvidos na translaçäo e as possíveis relaçöes entre o quadro citogenético da paciente e sua mäe e seus fenótipos