Search results for "X Chromosome"
showing 10 items of 80 documents
Localization of MRX82: A new nonsyndromic X-linked mental retardation locus to Xq24-q25 in a Basque family
2004
Clinical and molecular studies are reported on a Basque family (MRX82) with nonsyndromic X-linked mental retardation (XLMR) in five affected males. A total of 38 microsatellite markers were typed. The XLMR locus has been linked to DXS8067, DXS1001, DXS425, DXS7877, and DXS1183 with a maximum LOD score of 2.4. The haplotype studies and multipoint linkage analysis suggest a localization of the MRX82 locus to an interval of 7.6 Mb defined by markers DXS6805 and DXS7346, in Xq24 and Xq25, respectively. No gene contained in this interval has been so far associated with nonsyndromic mental retardation, except for GRIA3, disrupted by a balanced translocation in a female patient with bipolar affect…
Four unrelated patients with lubs X-linked mental retardation syndrome and different Xq28 duplications
2010
The Lubs X-linked mental retardation syndrome (MRXSL) is caused by small interstitial duplications at distal Xq28 including the MECP2 gene. Here we report on four novel male patients with MRXSL and different Xq28 duplications delineated by microarray-based chromosome analysis. All mothers were healthy carriers of the duplications. Consistent with an earlier report [Bauters et al. (2008); Genome Res 18: 847-858], the distal breakpoints of all four Xq28 duplications were located in regions containing low-copy repeats (LCRs; J, K, and L groups), which may facilitate chromosome breakage and reunion events. The proximal breakpoint regions did not contain known LCRs. Interestingly, we identified …
Prenatal diagnosis and carrier detection in mucopolysaccharidosis type II by mutation analysis. A 47,XXY male heterozygous for a missense point mutat…
1994
Identification of iduronate-2-sulphatase (IDS) gene mutations in patients with mucopolysaccharidosis type II (MPS II, Hunter syndrome) allows fast and reliable carrier detection and prenatal diagnosis. We describe here three cases of prenatal diagnosis by direct detection of the gene mutation. In addition to two affected male fetuses from two different families, a 47,XXY fetus carrying both the normal and the mutant allele was diagnosed in a third family. The latter pregnancy was carried to term and the child is obviously not affected by MPS II.
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…
Karyological studies in Coris julis (Pisces, Labridae).
1988
In the present investigation the diploid number 2n = 48 (NF = 58) has been determined for females, primary males, and secondary males of Coris julis from the Gulf of Palermo. Differentiated sex chromosomes have not been observed in the population under study.
FISH mapping of the sex-reversal region on human chromosome 9p in two XY females and in primates
2000
Accumulating evidence suggests that haploinsufficiency of a dosage-sensitive gene(s) in human chromosome 9p24.3 is responsible for the failure of testicular development and feminisation in XY patients with monosomy for 9p. We have used molecular cytogenetic methods to characterise the sex-reversing 9p deletions in two XY females. Fluorescence in situ hybridisation (FISH) with YACs from the critical 9p region containing an evolutionarily conserved sex-determining gene, DMRT1, is a very fast and reliable assay for patient screening. Comparative YAC mapping on great ape and Old and New World monkey chromosomes demonstrated that the critical region was moved from an interstitial position on the…
Sex differences in allelic frequencies of the 5-HT2C Cys23Ser polymorphism in psychiatric patients and healthy volunteers: findings from an associati…
2000
Polymorphisms in the serotonergic system are believed to play a role in the etiology and treatment of different psychiatric illnesses. The 5-HT2C receptor gene is X-linked, with a frequent mutation at nucleotide 68 leading to a Ser-->Cys transition at amino acid 23. Recent studies have demonstrated an impaired function of 5-HT2C receptors and an increased production of the major noradrenergic metabolite 3-methoxy-4-hydroxyphenylethyleneglycol in the cerebrospinal fluid among the subjects carrying the Ser23 allele (Lappalainen et al., 1999). Biol. Psychiatry 46:821). We genotyped patients with alcohol dependence, panic disorder without agoraphobia, generalized anxiety disorder, narcolepsy an…
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.
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…
Molecular Analysis of the Androgen Receptor Gene in 52 Patients with Complete or Partial Androgen Insensitivity Syndrome: A Collaborative Study
1992
In patients with androgen insensitivity syndrome (AIS), RFLP study of the androgen receptor gene made it possible to analyze whether deletions or mutations could be responsible for abnormalities in androgen responsiveness. We studied RFLPs of DNA from 25 46,XY patients with partial AIS (PAIS), defined as a concentration of androgen receptor in genital-skin fibroblasts less than 340 fmol/mg DNA, and DNA from 27 46,XY patients with complete AIS (CAIS) with no detectable androgen receptor site. DNA samples were digested with BamHI, EcoRI, HindIII and TaqI restriction enzymes and hybridized with three cDNA probes covering the three domains of the androgen receptor. When we had the maternal and …