1/4. Sex chromosome aneuploidy and bardet-biedl syndrome.The inheritance of bardet-biedl syndrome is thought to be autosomal recessive. Of the approximately 500 case reports in the literature, three patients were found to have sex chromosome aneuploidy. The authors describe two siblings with bardet-biedl syndrome, one of whom has a unique sex chromosome aneuploidy with mosaicism, including deletion of the short arm of the x chromosome (45,X/46,X,del(X)(p21)). The possible significance of sex chromosome aneuploidy and the bardet-biedl syndrome is discussed.- - - - - - - - - - ranking = 1keywords = sex chromosome, chromosome, sex (Clic here for more details about this article) |
2/4. The Laurence-moon-bardet-biedl syndrome: unresponsiveness to the action of testosterone, a possible mechanism.The pathogenesis of hypogonadism and hypogenitalism was investigated in a male patient with the complete form of the Laurence-moon-bardet-biedl syndrome. Synthetic gonadotropin-releasing hormone induced an increase in serum luteinizing hormone levels from 16.5 mIU/ml to 19.3 mIU/ml and in follicle-stimulating hormone levels from 18.5 mIU/ml to 25.9 mIU/ml. serum testosterone levels were normal and did not rise after stimulation with human chorionic gonadotropin. The administration of thyrotropin-releasing hormone resulted in an increase in serum thyrotropin levels from 9.0 microU/ml to 12.0 microU/ml. serum testoterone/estradiol-binding globulin, adrenocorticotropic hormone, and T3 resin uptake were normal. serum cortisol showed a normal diurnal variation. The sex chromatin test was negative and the karyotupe revealed a 46,XY chromosome pattern. On biopsy, the left testis lacked germinal cells and the right testis showed spermatogenic arrest. Signs of hypogonadism and hypogenitalism persisted after 11 months of testosterone treatment. In this patient the target-organ unresponsiveness resulted in hypogenitalism and hypogonadism.- - - - - - - - - - ranking = 0.00084750823368734keywords = chromosome, sex (Clic here for more details about this article) |
3/4. Heritable fragile sites on human chromosomes II. Distribution, phenotypic effects, and cytogenetics.Individuals and families have been documented in which there are a number of fragile sites on chromosomes. These include sites at 2q11, 10q23, 11q13, 16p124, 16q22, 20p11, and Xq27 or 28. Fragile sites reported in the literature are compiled. The cytogenetics of the sites is discussed. The phenotypic effects of the sites are considered, and it is speculated that homozygosity of the autosomal sites might be deleterious as is hemizygosity of the site on Xq. These sites are used in the previous report which documents the effect of tissue medium components on their expression.- - - - - - - - - - ranking = 0.0031243993150173keywords = chromosome (Clic here for more details about this article) |
4/4. The extra digit. A pointer to the eye?The syndrome associated with an extra digit which is commonly seen by the ophthalmologist is that of Laurence-moon-Biedl, with its well-known association with retinal dystrophy. However, there are several other syndromes in which there is polydactyly and an ocular malformation. Many have colobomata and microphthalmos. Other syndromes show various orbital and eyelid abnormalities, such as ptosis, hypertelorism, and lateral displacement of the canthi. In three syndromes other than the Laurence-moon-Biedl there is a retinal dystrophy. In trisomy 13 there is a severe retinal dysplasia, and in Bloom's syndrome excrescences on Bruch's membrane have been described. There have been several cases of asphyxiating thoracic dystrophy (Jeune's syndrome) described with a retinal dystrophy, and we present a case of the closely-related ellis-van creveld syndrome with a retinal dystrophy. We also present a case with a chromosomal defect (an addition to the short arm of chromosome 2), polydactyly, and a retinal dystrophy.- - - - - - - - - - ranking = 0.00062487986300346keywords = chromosome (Clic here for more details about this article) |