RESUMEN
A female twin with short stature, unusual facial appearance, widely spaced nipples, and coarctation of the aorta was found to have a peripheral blood lymphocyte karyotype of 45,X(43%)/46,X,idic(Y)(p11). Her twin brother, also short with similar facial appearance, had the same mosaicism (40% 45,X). Cultured skin fibroblast studies showed discrepant karyotypes of 45,X (100%) in the girl and 45,X (78%)/46,X,idic(Y)(p11) in the boy. The mother and the father had normal chromosomes. Comparison of 27 biochemical markers yielded a likelihood of monozygosity of 0.9977. This report documents the occurrence of discordant phenotypic sex in monozygotic twins, involving gonadal dysgenesis with an abnormal dicentric Y, which presumably occurred de novo, followed by anaphase lag probably before the occurrence of twinning. Unequal distribution of the two resultant cell lines in various tissues of each twin could account for the development of the very different phenotypes, apparently normal boy and Ullrich-Turner girl.
Asunto(s)
Enfermedades en Gemelos/genética , Enanismo/genética , Mosaicismo , Síndrome de Noonan/genética , Aberraciones Cromosómicas Sexuales/genética , Gemelos Monocigóticos , Cromosoma Y/ultraestructura , Dermatoglifia , Femenino , Marcadores Genéticos , Hernia Inguinal/genética , Humanos , Lactante , Masculino , Fenotipo , Desempeño Psicomotor , Aberraciones Cromosómicas Sexuales/patología , Análisis para Determinación del SexoRESUMEN
We observed an autosomal dominant disorder of abnormal upper lip, which resembles a poorly repaired cleft lip, malformed nose with broad bridge and flattened tip, lacrimal duct obstruction, malformed ears, and branchial cleft sinuses and/or linear skin lesions behind the ears in several persons in 3 families. In each of the 3 families, an affected parent had at least one affected child. Father-to-son transmission in one of these families ruled out X-linked inheritance. Other anomalies include coloboma, microphthalmia, auricular pits, lip pits, highly arched plate, dental anomalies, and subcutaneous cysts of the scalp. Premature graying of hair occurred in the affected adults. Growth retardation, developmental delay, and hand anomalies are variable components of the syndrome.
Asunto(s)
Anomalías Múltiples/genética , Región Branquial/patología , Genes Dominantes , Deformidades Congénitas de la Mano/genética , Labio/anomalías , Microftalmía/genética , Adulto , Preescolar , Femenino , Humanos , Masculino , SíndromeRESUMEN
A pregnant woman with indeterminate Duchenne muscular dystrophy (DMD) carrier status, but with DMD diagnosed in her deceased brother (unavailable for study), presented for prenatal diagnosis, intending to continue the pregnancy only if proven unaffected with DMD with near absolute certainty. Creatine kinase (CK) assays to clarify carrier status were inconclusive. Male sex in the fetus was identified, but DNA restriction fragment length polymorphism (RFLP) analysis was not yet available to this centre to investigate the possible transmission of the DMD gene, and the pregnancy was terminated. Tissue histology and dystrophin protein analysis demonstrated the absence of DMD. In a situation with proven maternal carrier status, future fetal inheritance of the opposite maternal X chromosome would indicate the presence of DMD. However, maternal carrier status remained in doubt through a second pregnancy, even with RFLP studies, and was finally established when dystrophin analysis confirmed the presence of DMD in the second fetus. Histologic findings are presented, contrasting features in the two fetuses. The value of dystrophin analysis for establishing the diagnosis of fetal DMD, in this case proving maternal carrier status in a difficult situation, and for demonstrating DMD gene:RFLP haplotype relationships is illustrated.