Search results for "X Chromosome"
showing 10 items of 80 documents
A new family with an SLC9A6 mutation expanding the phenotypic spectrum of Christianson syndrome
2016
Using targeted next generation sequencing, we have identified a splicing mutation (c.526-9_526-5del) in the SLC9A6 gene in a 9-year-old boy with mild intellectual disability (ID), microcephaly, and social interaction disabilities. This intronic microdeletion leads to the skipping of exon 3 and to an in-frame deletion of 26 amino acids in the TM4 domain. It segregates with cognitive impairment or learning difficulties in other members of the family. Mutations in SLC9A6 have been reported in X-linked Christianson syndrome associating severe to profound intellectual deficiency and an Angelman-like phenotype with microcephaly, absent speech, ataxia with progressive cerebellar atrophy, ophthalmo…
First report of X-linked hypohidrotic ectodermal dysplasia with a hemizygous c.1142G > C in the EDA gene: variant of uncertain significance or new pa…
2021
AbstractBackgroundHypohidrotic Ectodermal Dysplasia (HED) is a genetic disorder which affects structures of ectodermal origin. X-linked hypohidrotic ectodermal dysplasia (XLHED) is the most common form of disease. XLHED is characterized by hypotrichosis, hypohydrosis and hypodontia. The cardinal features of classic HED become obvious during childhood.Identification of a hemizygous EDA pathogenic variant in an affected male confirms the diagnosis.Case presentationWe report on a male newborn with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. Gene panel sequencing identified a new hemizygous missense variant of uncertain significanc…
Retroelements: tools for sex chromosome evolution
2003
Many eukaryotic taxa inherit a heteromorphic sex chromosome pair. It is a generally accepted hypothesis that the sex chromosome pair is derived from a pair of homologous autosomes that has developed after the occurrence of a sex differentiator in an evolutionary process into two structurally and functionally different partners. In most of the analyzed systems the occurrence of the dominant sex differentiator is paralleled by the suppression of recombination within and close by that region. The recombinational isolation can spread in an evolutionary selection process from neighboring regions finally over the whole chromosome. Suppression of recombination strongly biases the distribution of r…
H-Y antigen in the teleost.
1979
H-Y antigen, presumably the product of mammalian testis-determining genes, has been detected in three species of teleost fish, Xiphophorus maculatus, Haplochromis burtoni, and Oryzias latipes, and in hybrids of the genus Tilapia. In X. maculatus H-Y was most readily detected in YY males, suggesting that a genetic determinant of H-Y antigen expression may exist on the teleost Y-chromosome. Although H-Y was detected in males and not in females in each of the species that we studied, male heterogamety has not been firmly established for H. burtoni. Thus despite the extreme phlyogenetic conservation of H-Y genes and their association with the Y-chromosome, it remains open to question whether H-…
“Masked” Philadelphia chromosome resulting from a t(X;22) in chronic myeloid leukemia
1988
Abstract A rare cytogenetic finding in chronic myeloid leukemia is reported. It consisted in a “masked” Philadelphia chromosome, resulting from an unusual translocation between chromosomes #22 and X. The t(X;22) was present in 100% of direct and cultured bone marrow cell preparations. Chromosome #9 did not seem to be involved in the formation of the Ph marker. Involvement of the X chromosome in karyotypic changes of hematologic diseases, with particular respect to chronic myeloid leukemia, is discussed.
Distinct Xp11.2 breakpoints in two renal cell carcinomas exhibiting X;autosome translocations
1995
Several human renal cell carcinomas with X;autosome translocations have been reported in recent years. The t(X; I)(p11.2;q21) appears to be a specific primary anomaly, suggesting that tumors with this translocation form a distinct subgroup of RCC. Here we report two new cases, one with a t(X;10)(p11.2;q23), the other with a t(X;1)(p11.2;p34). The common breakpoint in Xp11.2 suggests that they belong to the above-mentioned subset of RCC. Using FISH in conjunction with X-specific YAC clones, we demonstrate that the two new cases exhibited distinct breakpoints within Xp11.2. (C) 1995 Wiley-Liss, Inc.
Two distinct genomic regions, harbouring the period and fruitless genes, affect male courtship song in Drosophila montana
2012
Acoustic signals often have a significant role in pair formation and in species recognition. Determining the genetic basis of signal divergence will help to understand signal evolution by sexual selection and its role in the speciation process. An earlier study investigated quantitative trait locus for male courtship song carrier frequency (FRE) in Drosophila montana using microsatellite markers. We refined this study by adding to the linkage map markers for 10 candidate genes known to affect song production in Drosophila melanogaster. We also extended the analyses to additional song characters (pulse train length (PTL), pulse number (PN), interpulse interval, pulse length (PL) and cycle nu…
The new gene DmX from Drosophila melanogaster encodes a novel WD-repeat protein
1998
DmX is a novel gene from Drosophila melanogaster located on the X chromosome in region 5D5/6-E1. The molecular analysis of the genomic and cDNA sequences of DmX shows that the gene spans appr. 16kb and displays a mosaic structure with 15 exons. The 12kb long DmX transcript is present in Drosophila embryos, larvae and adults of both sexes. The open reading frame of DmX encodes a novel WD-repeat protein, containing at least 30 WD-repeat units. WD-repeat proteins contain a conserved motif of approximately 40 amino acids (aa), usually ending with the dipeptide Trp-Asp (WD). Homologues of the DmX gene exist in other dipteran species, in Caenorhabditis elegans and human, revealing that DmX is an …
Distribution of heterochromatin on the mitotic chromosomes of Musca domestica L. in relation to the activity of male-determining factors
1998
In the housefly, male sex is determined by a dominant factor, M, located either on the Y, on the X, or on any of the five autosomes. M factors on autosome I and on fragments of the Y chromosome show incomplete expressivity, whereas M factors on the other autosomes are fully expressive. To test whether these differences might be caused by heterochromatin-dependent position effects, we studied the distribution of heterochromatin on the mitotic chromosomes by C-banding and by fluorescence in situ hybridization of DNA fragments amplified from microdissected mitotic chromosomes. Our results show a correlation between the chromosomal position of M and the strength of its male-determining activity…
Evidence for male XO sex-chromosome system in Pentodon bidens punctatum (Coleoptera Scarabaeoidea: Scarabaeidae) with X-linked 18S-28S rDNA clusters
2004
In scarab beetle species of the genus Pentodon, the lack of analysis of sex chromosomes in females along with the poor characterization of sex chromosomes in the males, prevented all previous investigations from conclusively stating sex determination system. In this study, somatic chromosomes from females and spermatogonial chromosomes from males of Pentodon bidens punctatum (Coleoptera: Scarabaeoidea: Scarabaeidae) from Sicily have been analyzed using non-differential Giemsa staining. Two modal numbers of chromosomes were obtained: 2n = 20 and 19 in females and males, respectively. This finding along with other karyological characteristics such as the occurrence of one unpaired, heterotypi…