Molecular and cytogenetic characterization of a non‐mosaic isodicentric Y chromosome in a patient with Klinefelter syndrome

Heinritz, Wolfram; Kotzot, Dieter; Heinze, Stefan; Kujat, Annegret; Kleemann, W. J.; Froster, Ursula G.

doi:10.1002/ajmg.a.30446

Cited by 7 publications

(11 citation statements)

References 19 publications

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“…In 2005, Heinritz reported an adult male with Klinefelter phenotype and an isodicentric Y chromosome (47, XX, + idic (Y)(q12)). Although it is highly likely that that case also had breakage and fusion at the PAR-2 [13], the gene dosage and break points were not confirmed by other methods. Our case should be the first documented case of idic(Yp) with breakage and fusion at the PAR-2.…”

Section: Case Reportmentioning

confidence: 84%

A non-mosaic isodicentric Y chromosome resulting from breakage and fusion at the Yq pseudo-autosomal region in a fetus

Kuan

Chen

et al. 2013

J Assist Reprod Genet

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The dicentric Y chromosomes are the most commonly found in the structural aberration of Y chromosome. If the dicentric chromosome has completely symmetric arms, it is considered an isodicentric chromosome. The sites of breakage and fusion at Yp and Yq are variable, but breakage and fusion at the pseudo-autosomal region has never been reported. Herein we reported identification de novo isodicentric (Yq12) in a fetus. The fusion occurred at Yq pseudo-autosomal region very close the telomere and resulted in duplication of Y chromosome. The baby was grossly normal at birth. In conclusion, isodicentric Y chromosome could result from breakage and fusion at the Yq pseudo-autosomal region.

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Section: Case Reportmentioning

confidence: 84%

A non-mosaic isodicentric Y chromosome resulting from breakage and fusion at the Yq pseudo-autosomal region in a fetus

Kuan

Chen

et al. 2013

J Assist Reprod Genet

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“…Throughout our analysis, we examine cases where recombination occurs at a rate of d per paralog pair, per generation. The probability that a single recombination event is a crossover, which generates an abnormal (sterile) Y chromosome (e.g., Repping et al 2002;Heinritz et al 2005;Lange et al 2009), is equal to the constant c . The remainder of recombination events (1 À c) represent gene conversion events between duplicate pairs.…”

Section: Model and Resultsmentioning

confidence: 99%

“…Crossovers between Y-linked genes can generate acentric and dicentric Y chromosomes, resulting in infertility and disruption of the sex determination pathway (e.g., Repping et al 2002;Heinritz et al 2005;Lange et al 2009). Considering both gene conversion and crossing over on the Y, recombination can be viewed as a factor that either constrains (via gene conversion) or promotes (via crossing over) Y chromosome degeneration.…”

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confidence: 99%

Gene Duplication, Gene Conversion and the Evolution of the Y Chromosome

Connallon

Clark

2010

Genetics

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Nonrecombining chromosomes, such as the Y, are expected to degenerate over time due to reduced efficacy of natural selection compared to chromosomes that recombine. However, gene duplication, coupled with gene conversion between duplicate pairs, can potentially counteract forces of evolutionary decay that accompany asexual reproduction. Using a combination of analytical and computer simulation methods, we explicitly show that, although gene conversion has little impact on the probability that duplicates become fixed within a population, conversion can be effective at maintaining the functionality of Y-linked duplicates that have already become fixed. The coupling of Y-linked gene duplication and gene conversion between paralogs can also prove costly by increasing the rate of nonhomologous crossovers between duplicate pairs. Such crossovers can generate an abnormal Y chromosome, as was recently shown to reduce male fertility in humans. The results represent a step toward explaining some of the more peculiar attributes of the human Y as well as preliminary Y-linked sequence data from other mammals and Drosophila. The results may also be applicable to the recently observed pattern of tetraploidy and gene conversion in asexual, bdelloid rotifers.

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“…The behavior of the man was described as aggressive with rapid alterations of the mood and a naive and inappropriate social performance. The LH and FSH levels were increased, but testosterone levels were lower than normal [Heinritz et al, 2005]. Normally, psychological and behavioral problems like violence, aggressiveness, and a low IQ are the main features of males with 48,XXYY and are very untypical for KS patients [Heinritz et al, 2005].…”

Section: Klinefelter Patients With Additional Aberrations On the Y Chmentioning

confidence: 99%

“…An interesting case about a 31-year-old male patient with an in part Klinefelter phenotype and an isodicentric Y-chromosome was reported by Heinritz et al [2005]. The karyotype was indicated as 47,XX,+idic(Y)(q12).…”

Section: Klinefelter Patients With Additional Aberrations On the Y Chmentioning

confidence: 99%

Chromosomal Variants in Klinefelter Syndrome

Frühmesser

Kotzot²

2011

Sex Dev

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Klinefelter syndrome (KS) describes the phenotype of the most common sex chromosome abnormality in humans and occurs in one of every 600 newborn males. The typical symptoms are a tall stature, narrow shoulders, broad hips, sparse body hair, gynecomastia, small testes, absent spermatogenesis, normal to moderately reduced Leydig cell function, increased secretion of follicle-stimulating hormone, androgen deficiency, and normal to slightly decreased verbal intelligence. Apart from that, amongst others, osteoporosis, varicose veins, thromboembolic disease, or diabetes mellitus are observed. Some of the typical features can be very weakly pronounced so that the affected men often receive the diagnosis only at the adulthood by their infertility. With a frequency of 4%, KS is described to be the most common genetic reason for male infertility. The most widespread karyotype in affected patients is 47,XXY. Apart from that, various other karyotypes have been described, including 46,XX in males, 47,XXY in females, 47,XX,der(Y), 47,X,der(X),Y, or other numeric sex chromosome abnormalities (48,XXXY, 48,XXYY, and 49,XXXXY). The focus of this review was to abstract the different phenotypes, which come about by the various karyotypes and to compare them to those with a ‘normal’ KS karyotype. For that the patients have been divided into 6 different groups: Klinefelter patients with an additional isochromosome Xq, with additional rearrangements on 1 of the 2 X chromosomes or accordingly on the Y chromosome, as well as XX males and true hermaphrodites, 47,XXY females and Klinefelter patients with other numeric sex chromosome abnormalities. In the latter, an almost linear increase in height and developmental delay was observed. Men with an additional isochromosome Xq show infertility and other minor features of ‘normal’ KS but not an increased height. Aside from the infertility, in male patients with other der(X) as well as der(Y) rearrangements and in XXY women no specific phenotype is recognizable amongst others due to the small number of cases. The phenotype of XX males depends on the presence of SRY (sex-determining region Y) and the level of X inactivation at which SRY-negative patients are generally rarely observed.

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Molecular and cytogenetic characterization of a non‐mosaic isodicentric Y chromosome in a patient with Klinefelter syndrome

Cited by 7 publications

References 19 publications

A non-mosaic isodicentric Y chromosome resulting from breakage and fusion at the Yq pseudo-autosomal region in a fetus

A non-mosaic isodicentric Y chromosome resulting from breakage and fusion at the Yq pseudo-autosomal region in a fetus

Gene Duplication, Gene Conversion and the Evolution of the Y Chromosome

Chromosomal Variants in Klinefelter Syndrome

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