Incidence of major chromosome aberrations in 12,319 newborn infants in Tokyo

Genetic counseling prior to assisted reproductive technology

BACKGROUND

Reproductive medicine deals with fertility and is closely related to heredity. In reproductive medicine, it is necessary to provide genetic information for the patients prior to assisted reproductive technology (ART). Japan Society for Reproductive Medicine (JSRM) requires doctors involved in reproductive medicine to have standard knowledge of reproductive genetics and knowledge of reproductive medicine, which is covered in their publication, "required knowledge of reproductive medicine."

METHODS

With the aim of providing straightforward explanations to patients in the clinical situation at pre-ART counseling, we provide the following five topics, such as (a) risk of birth defects in children born with ART, (b) chromosomal abnormalities, (c) Y chromosome microdeletions (YCMs), (d) possible chromosomal abnormal pregnancy in oligospermatozoa requiring ICSI (intracytoplasmic sperm injection), and (e) epigenetic alterations.

MAIN FINDINGS

The frequency of chromosome abnormalities in infertile patients is 0.595%-0.64%. YCMs are observed in 2%-10% of severe oligospermic men. High incidence of spermatozoa with chromosomal abnormalities has been reported in advanced oligospermia and asthenozoospermia that require ICSI. Some epigenetic alterations were reported in the children born with ART.

CONCLUSION

Certain genetic knowledge is important for professionals involved in reproductive medicine, even if they are not genetic experts.

The epidemiology of sex chromosome abnormalities

Sex chromosome abnormalities (SCAs) are characterized by gain or loss of entire sex chromosomes or parts of sex chromosomes with the best-known syndromes being Turner syndrome, Klinefelter syndrome, 47,XXX syndrome, and 47,XYY syndrome. Since these syndromes were first described more than 60 years ago, several papers have reported on diseases and health related problems, neurocognitive deficits, and social challenges among affected persons. However, the generally increased comorbidity burden with specific comorbidity patterns within and across syndromes as well as early death of affected persons was not recognized until the last couple of decades, where population-based epidemiological studies were undertaken. Moreover, these epidemiological studies provided knowledge of an association between SCAs and a negatively reduced socioeconomic status in terms of education, income, retirement, cohabitation with a partner and parenthood. This review is on the aspects of epidemiology in Turner, Klinefelter, 47,XXX and 47,XYY syndrome.

Klinefelter syndrome: From pediatrics to geriatrics

BACKGROUND

Klinefelter syndrome (KS) is one of the major causes of nonobstructive azoospermia (NOA). Microdissection testicular sperm extraction (micro-TESE) is often performed to retrieve sperm. Infertility specialists have to care for KS patients on a lifelong basis.

METHODS

Based on a literature review and our own experience, male infertility treatment and KS pathophysiology were considered on a lifelong basis.

MAIN FINDINGS

Patients diagnosed early often have an increased number of aberrant X chromosomes. Cryptorchidism and hypospadias are often found, and surgical correction is required. Cryopreservation of testicular sperm during adolescence is an issue of debate because the sperm retrieval rate (SRR) in KS patients decreases with age. The SRR in adult KS patients is higher than that in other patients with NOA; however, low testosterone levels after micro-TESE will lower the general health and quality of life. KS men face a number of comorbidities, such as malignancies, metabolic syndrome, diabetes, cardiovascular disease, bone disease, and immune diseases, which ultimately results in increased mortality rates.

CONCLUSION

A deeper understanding of the pathophysiology of KS and the histories of KS patients before they seek infertility treatment, during which discussions with multidisciplinary teams are sometimes needed, will help to properly treat these patients.

Changes in the cohort composition of turner syndrome and severe non-diagnosis of Klinefelter, 47,XXX and 47,XYY syndrome: a nationwide cohort study

Background

Knowledge on the prevalence of sex chromosome abnormalities (SCAs) is limited, and delayed diagnosis or non-diagnosis of SCAs are a continuous concern. We aimed to investigate change over time in incidence, prevalence and age at diagnosis among Turner syndrome (TS), Klinefelter syndrome (KS), Triple X syndrome (Triple X) and Double Y syndrome (Double Y).

Methods

This study is a nationwide cohort study in a public health care system. The Danish Cytogenetic Central Registry (DCCR) holds information on all karyotypes performed in Denmark since 1961. We identified all individuals in the DCCR with a relevant SCA during 1961–2014; TS: n = 1156; KS: n = 1235; Triple X: n = 197; and Double Y: n = 287. From Statistics Denmark, which holds an extensive collection of data on the Danish population, complete data concerning dates of death and migrations in and out of Denmark were retrieved for all individuals.

Results

The prevalence among newborns was as follows: TS: 59 per 100,000 females; KS: 57 per 100,000 males; Triple X: 11 per 100,000 females; and Double Y: 18 per 100,000 males. Compared with the expected number among newborns, all TS, 38% of KS, 13% of Triple X, and 18% of Double Y did eventually receive a diagnosis. The incidence of TS with other karyotypes than 45,X (P < 0.0001), KS (P = 0.02), and Double Y (P = 0.03) increased during the study period whereas the incidence of 45,X TS decreased (P = 0.0006). The incidence of Triple X was stable (P = 0.22).

Conclusions

The prevalence of TS is higher than previously identified, and the karyotypic composition of the TS population is changing. Non-diagnosis is extensive among KS, Triple X and Double Y, whereas all TS seem to become diagnosed. The diagnostic activity has increased among TS with other karyotypes than 45,X as well as among KS and Double Y.

Klinefelter Syndrome: Integrating Genetics, Neuropsychology, and Endocrinology

Although first identified over 70 years ago, Klinefelter syndrome (KS) continues to pose substantial diagnostic challenges, as many patients are still misdiagnosed, or remain undiagnosed. In fact, as few as 25% of patients with KS are accurately diagnosed and most of these diagnoses are not made until adulthood. Classic characteristics of KS include small testes, infertility, hypergonadothropic hypogonadism, and cognitive impairment. However, the pathophysiology behind KS is not well understood, although genetic effects are also thought to play a role. For example, recent developments in genetics and genomics point to a fundamental change in our understanding of KS, with global epigenetic and RNA expression changes playing a central role for the phenotype. KS is also associated with more general health markers, including higher morbidity and mortality rates and lower socioeconomic status (which likely affect both morbidity and mortality). In addition, hypogonadism is associated with greater risk of metabolic syndrome, type 2 diabetes, cardiovascular disease, breast cancer, and extragonadal germ cell tumors. Medical treatment typically focuses on testosterone replacement therapy (TRT), although the effects of this therapy have not been studied rigorously, and future studies need to evaluate the effects of TRT on metabolic risk and neurocognitive outcomes. This review presents a comprehensive interdisciplinary examination of recent developments in genetic, endocrine, and neurocognitive science, including the study of animal models. It provides a number of recommendations for improving the effectiveness of research and clinical practice, including neonatal KS screening programs, and a multidisciplinary approach to KS treatment from childhood until senescence.

Morbidity and mortality in Klinefelter syndrome (47,XXY)

Klinefelter syndrome (KS) (47,XXY) is the most common sex chromosome disorder in man and is a relatively common cause of male infertility and hypogonadism. The syndrome has been known since 1942, and many reports of different diseases associated with KS have been reported since that, but a more systematic knowledge about the long-term outcome was not described until the last decade, where nation-wide epidemiological studies were reported from Britain and Denmark. We here review the epidemiological data from two cohorts of patients with KS in Denmark and Britain, showing a significant increase in both mortality and morbidity from a variety of different causes. Mortality was increased by 50% (SMR 1.5 or HR 1.4) corresponding to a median loss of approximately 2 years. The risk of being admitted to hospital with any diagnosis was increased by 70%. The underlying reason for the poorer health in KS may be caused by interaction of genetic, hormonal and socio-economic factors.

CONCLUSION

Both morbidity and mortality are significantly increased in Klinefelter syndrome with a 50% increase in mortality risk and a 70% increase in risk of being admitted to hospital.

A cytogenetic survey of 449 patients in a Japanese institution for the mentally retarded

A cytogenetic survey was carried out on 449 patients (261 males and 188 females) in an institution for the mentally retarded in Japan. A total of 37 patients (8.1%) were shown to have chromosome abnormalities. There were 33 individuals (7.3%) with 21 trisomy. In addition, we found one patient with 46,XY/47,XY,+12p, one with 46,XY,r(22), and one with 45,XY,-13,-14,+t(13q14q). Only one female was found to have an abnormal sex chromosome constitution, 47,XXX. The significant contribution of chromosome abnormalities in the etiology of mental retardation is also shown in the present survey. The most common chromosome abnormality was 21 trisomy, as seen in other similar surveys.

Update in andrology

CONTEXT

This is an invited review based on a presentation at the 2007 Annual Scientific Meeting of The Endocrine Society.

OBJECTIVE

The objective of the review was to highlight a selection of the most important peer-reviewed papers in andrology published over the last 1-2 yr.

EVIDENCE ACQUISITION

This was a comprehensive survey of all papers published in major endocrinology journals over the last 2 yr augmented by personal knowledge and literature searching as well as an e-mail survey of more than 40 leading andrologists.

EVIDENCE SYNTHESIS

From the list of suggested papers, the findings of a short list considered the most important were reviewed, aiming to focus on findings that influence thinking and practice in the field of andrology.

CONCLUSIONS

Important advances highlighted included establishing genetic paternity for men with Klinefelter's syndrome as a realistic therapeutic option via testicular sperm aspiration coupled with intracytoplasmic sperm injection in vitro fertilization, using population registry linkage data to define the natural history of Klinefelter's syndrome in the community and identifying active cellular uptake mechanisms for SHBG-bound testosterone challenging the quasiaxiomatic status of the free hormone hypothesis. Other important recent contributions reviewed are on testosterone effects on the prostate, hormonal male contraception, possible temporal trends in blood testosterone concentrations in American men, and The Endocrine Society's position papers on testosterone assays and guidelines on testosterone prescribing.

How sexually dimorphic are we? Review and synthesis

The belief that Homo sapiens is absolutely dimorphic with the respect to sex chromosome composition, gonadal structure, hormone levels, and the structure of the internal genital duct systems and external genitalia, derives from the platonic ideal that for each sex there is a single, universally correct developmental pathway and outcome. We surveyed the medical literature from 1955 to the present for studies of the frequency of deviation from the ideal male or female. We conclude that this frequency may be as high as 2% of live births. The frequency of individuals receiving "corrective" genital surgery, however, probably runs between 1 and 2 per 1,000 live births (0.1-0.2%). Am. J. Hum. Biol. 12:151-166, 2000. Copyright 2000 Wiley-Liss, Inc.

How sexually dimorphic are we? Review and synthesis

The belief that Homo sapiens is absolutely dimorphic with the respect to sex chromosome composition, gonadal structure, hormone levels, and the structure of the internal genital duct systems and external genitalia, derives from the platonic ideal that for each sex there is a single, universally correct developmental pathway and outcome. We surveyed the medical literature from 1955 to the present for studies of the frequency of deviation from the ideal male or female. We conclude that this frequency may be as high as 2% of live births. The frequency of individuals receiving "corrective" genital surgery, however, probably runs between 1 and 2 per 1,000 live births (0.1-0.2%). Am. J. Hum. Biol. 12:151-166, 2000. Copyright 2000 Wiley-Liss, Inc.

Cytogenetic pattern in leukemic cells of patients with constitutional chromosome anomalies

Acquired karyotypic changes analyzed by banding techniques in 21 patients with a malignant hematologic disorder and a major constitutional chromosome anomaly, including ten patients with trisomy 21, five patients with a balanced translocation, and six patients with a sex chromosome anomaly. Detailed karyotypic findings were ascertained in 28 additional patients reported in the literature. Some striking differences were observed in the combined material of the present series and cases previously published as regards (a) distribution of morphological leukemia types among patients with different types of constitutional anomalies, and (b) incidence and type of acquired chromosomal abnormality among patients with different types of constitutional anomalies.

United States survey on chromosome mosaicism and pseudomosaicism in prenatal diagnosis

The survey of the incidence of chromosome mosaicism and pseudomosaicism detected in prenatal diagnosis included data from approximately 60 000 genetic amniocenteses in the United States. There were 59 participating cytogenetic laboratories nationwide. The overall incidence of chromosome mosaicism was 0.25 per cent (range of 0-0.89 per cent). The average frequency of pseudomosaicism involving multiple cells or clones was 0.7 per cent (range of 0-11.21 per cent). The frequency of single cell or clone pseudomosaicism was 2.47 per cent (range of 0-11.49 per cent). In cases of pseudomosaicism with trisomy, the most frequently involved chromosome was number 2; occurrence rates of trisomies 7,X,9,17 and 20 were also relatively high. In cases of pseudomosaicism with structural abnormalities, this survey showed an association between relative chromosome size and the frequency of involvement in structural rearrangement. Data on a total of 185 cases of chromosome mosaicism collected in this survey as well as from other documented sources showed 89 cases involved an autosome, 73 cases a sex chromosome, and 23 a marker chromosome. The frequency of noticeable phenotypic abnormalities was highest (37.8 per cent) in the autosomal mosaics and lowest (10.5 per cent) in the sex chromosome mosaics. The average rate for cytogenetic confirmation was 70 per cent.

Epidemiology of trisomy 21: population, peri- and antenatal data

In Down's syndrome, incidence of 1 0/00-2 0/00 have been reported in chromosomal surveys of consecutive liveborn infants and in population studies. Much attention has been focused on the influence of the decline in mean maternal age on the incidence of Down's syndrome. Decline in incidence and unchanged incidences have been reported. For mothers over 35 years old, a rise in incidence has been found in recent years in some societies. Environmental factors or seasonal fluctation might cause this trend. Data from antenatal diagnosis show a 30% higher incidence of Down's syndrome for age groups over 35 than population studies do. Late abortions of trisomic fetuses, a high perinatal mortality, and a small rise in incidence for higher maternal ages in recent years may account for this fact. With the growing tendency toward younger maternal age at childbirth, paternal factors also have to be considered. Between 10% and 30% paternal failures have been found by nondisjunction studies applying chromosomal variants. The rate of paternal failures may reflect environmental influences and young maternal age distribution. Recently, an increase in trisomy 21 children of mothers in the age group 30-39 who are pill users has been observed. The positive sex ratio of male Down's syndrome patients has been reversed in patients born to mothers using hormonal contraception. The mortality rate, in Down's syndrome is still high in early childhood, especially perinatally and in the 1st year of life. For the late 1940s in Denmark, newborns with Down's syndrome had a mortality rate of 53% in the 1st year of life. In the late 1960s and early 1970s, the rate had fallen to 22%. The main causes of death were congenital heart disease in connection with infections, especially pneumonia. Cot death might be more common in Down's syndrome. After the age of 1 year, mortality is reduced considerably and more and more cases will survive early childhood and live to rather old ages.