XYY chromosomal complement,proven by fluorescence,in a child with trisomy 21: 48,XYY,21+

Summary Clinical, cytogenetic, autoradiographic, fluorescence microscopic and dermatoglyphic data of a boy with 48,XYY,21+ karyotype are reported. The child had some clinical anomalies common in Down's syndrome. DNA replication of the 2 Y chromosomes was synchronous in all labelled metaphases. It was possible to distinguish the two Y's from the pairs No. 21-22 under the fluorescence microscope and single as well as double Y bodies were demonstrated in buccal mucosa cells. Dermatoglyphic investigation revealed some features typical for mongolism.     

Dentition of a 48,XYY,+21 male

Summary Although the dentition of a 48,XYY,+21 male showed some typical features of Down's syndrome, metric analysis indicated a marked increase in tooth size particularly for early developing teeth. The extra Y chromosome can influence phenotypic expression, overcoming the superimposed effects of the additional 21 chromosome.     

Incidence of 47,XYY males: Implications of the production of 47,XYY offspring by 47,XYY males

Abstract

Chromosomally normal 46,XY males can have 47,XYY male offspring as a result of fertilization of a normal ovum by a YY spermatozoon, produced by nondisjunction in the second meiotic division or by mitotic nondisjunction of the Y chromosome in early stages of embryonic development of a 46,XY fetus. If such meiotic and mitotic nondisjunctions were random events and if these were the only source of 47,XYY males in the population, the incidence of 47,XYY males would remain constant. Two cases have been reported, however, in which 47,XYY males produced 47,XYY male offspring. If there are 47,XYY males who are a source of 47,XYY males in the population, there is the possibility that the incidence of 47,XYY males is changing. A discrete‐generation model is presented which describes (1) the change in incidence of 47,XYY males from one generation to the next; (2) the incidence at equilibrium; and (3) the incidence as a function of the probability that a 47.XYY male has a 47,XYY offspring, and as a function of the mean number of offspring of 47,XYY males relative to the mean number of offspring of 46,XY males.     

47,XYY Syndrome and Male Infertility

Men with 47,XYY syndrome present with varying physical attributes and degrees of infertility. A retrospective chart review was performed on a male infertility and genetic anomaly database. Three patients with 47,XYY were found. Each presented with > 2 years of infertility. All were tall with elevated body mass indices. Scrotal findings ranged from normal to atrophic testicles. Semen analyses demonstrated oligospermia and varying endocrine profiles. Because of the diverse phenotype and potential lack of symptoms, identification and diagnosis of men with 47,XYY syndrome may be difficult. We recommend careful screening of 47,XYY patients and referral to primary physicians for long-term follow-up for increased incidence of health-related comorbidities.Key words: Infertility syndromesThe 47,XYY sex chromosome variation is the most common sex chromosome anomaly after Klinefelter syndrome (47,XXY),^1–3 occurring in approximately 1 out of 1000 live male births.^4,5 Parental nondisjunction at meiosis II resulting in an extra Y chromosome produces a 47,XYY karyotype in the affected offspring.^6–8 46,XY/47,XYY mosaics from parental nondisjunction during cell division after postzygotic mitosis can result in addition of the extra Y chromosome in early embryonic development.^6,8Most patients with 47,XYY have a delayed diagnosis, with a median age of 17.1 years at diagnosis, as was shown in a Danish cohort study.⁹ Although most have no phenotypic abnormalities, XYY boys are at greater risk for behavioral problems, mild learning disability, delayed speech and language development, and tall stature.¹⁰ Studies have increasingly reported an association between 47,XYY and fertility problems, noting an increased incidence of chromosomally abnormal spermatozoa in the semen of men with 47,XXY syndrome.^7,11–15 This greater prevalence of hyperhaploid sperm results in an increased risk of passing the extra Y chromosome to offspring.¹⁴ Men with 47,XXY syndrome can have variable sperm counts, ranging from normal to azoospermia.^{3,8,14,16–18}Here we review pertinent findings on physical examination and laboratory evaluation in three men with 47,XXY syndrome diagnosed during infertility evaluation as well as review the available literature on the subject, with special emphasis on male fertility effects.     

XYY spermatogenesis in XO/XY/XYY mosaic mice

The relative frequencies of XYY and XY cells in XO/XY/XYY mosaic mice were compared between somatic cells (bone marrow) and spermatogonia, and between spermatogonia and pachytene or MI spermatocytes. The results indicated there was no selection either for or against XYY spermatogonia. There was, however, a strong selection against XYY spermatocytes during pachytene, with their almost total elimination by the first meiotic metaphase. At pachytene, most XYY cells had trivalent or X univalent/YY bivalent configurations. These findings are contrasted with previous studies of XYY spermatogenesis in mice and are discussed with respect to a model that invokes sex-chromosome univalence as the cause of XYY spermatogenic failure.     

Les Hommes XYY

The constitution 47,XYY is the second most common dysgonosomy, occurring at frequencies of between 1/851 to 1 1.000 male births. A part from their large size, these men are physically no different from the population in general. Their occasional learning difficulties are easily resolved by family and educational support. As children, they tend to be quick tempered but we not agressive towards others. They have difficulty in concentrating and appear to be disturbed by an unstable family environment which can lead to problems of delinquency. Careful upbringing allows them, as adults to adjust well in family, conjugal and social situations. The majority are fertile and their offspring normal, since the supernumary Y is eliminated during spermatogenesis. When regulation of this process is defective, oligospermy or azoospermy appears to result. However, the proportion of XYY subjects which are sterile due to this phenomenons is not well known. Likewise, their eventuel predisposition to hematological malignancies has not been well investigated. Further studies should resolve these questions.     

Partial XYY syndrome

Summary A 13-year-old boy with 47 chromosomes, an extra small metacentric chromosome and karyotype 47,XY,?Yq- is presented. He has psychiatric symptoms typical of boys with karyotype 47,XYY as seen in the tabulated results of a psychiatric study of 22 boys with the XYY syndrome, examined at the Cytogenetic Laboratory, Århus State Hospital, Risskov.

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Zusammenfassung Es wird über einen 13 Jahre alten Jungen berichtet mit 47 Chromosomen, einem zusätzlichen kleinen metazentrischen Chromosom und der Karyotype 47,XY, ?Yq-. Er weist die typischen psychischen Symptome für Jungen mit der Karyotype 47,XYY auf, wie man aus den tabellarisch dargestellten Ergebnissen der psychiatrischen Untersuchung von insgesamt 22 Jungen mit XYY-Syndrom, die am cytogenetischen Labor, Århus State Hospital, Risskov, untersucht wurden, ersehen kann.

     

Normal meiosis in two 47,XYY men

Summary Details of testicular histology and meiosis are given for two 47,XYY men, one an oligospermic childless individual, the other a fertile man with near-normal spermatogenic activity in his testes. Examination of the chromosomes at meiosis, with Q and C staining, gave no evidence for the occurrence of the second Y chromosome in the germ line of either individual.     

Sperm chromosome complements in a 47,XYY man

Summary Human sperm chromosomes from a 47,XYY male were examined using the direct method of sperm chromosome analysis with two modifications in the semen processing. A total of 75 sperm complements was karyotyped and all of these contained one sex chromosome. The percentages of X-and Y-bearing sperm were 53% and 47%, respectively. There were 10 sperm with autosomal chromosomal abnormalities. The frequencies of numerical (4.0%), structural (10.6%), and total (13.3%) abnormalities were not significantly different from the frequencies observed in normal donors in our laboratory. Our results do not support the suggestion that XYY males have an increased risk of aneuploid progeny as a result of secondary non-disjunction or interchromosomal effects. They do support the hypothesis that one Y chromosome is eliminated in the germ cells of XYY males. However since our study provides the first information on sperm chromosomes in an XYY male, further studies on other XYY men are required.     

Malformed genitalia in the 47,XYY genotype.

A 5 10/12 year-old boy with a 47,XYY karyotype, micropenis, scrotal hypospadias and right testicular regression is described. Normal for age basal plasma testosterone levels which increased after hCG stimulation were interpreted as an adequate response of the left testicular Leydig cells. The review of similar cases did not permit definite conclusions concerning the relationship between the abnormal genitalia and the XYY karyotype.