Down syndrome and male fertility: PCR-derived fingerprinting, serological and andrological investigations

Endocrine, auxological and metabolic profile in children and adolescents with Down syndrome: from infancy to the first steps into adult life

Down syndrome (DS) is the most common chromosomal disorder worldwide. Along with intellectual disability, endocrine disorders represent a remarkable share of the morbidities experienced by children, adolescents and young adults with DS. Auxological parameters are plotted on syndrome-specific charts, as growth rates are reduced compared to healthy age- and gender-matched peers. Furthermore, children with DS are at increased risk for thyroid dysfunctions, diabetes mellitus, osteopenia and obesity compared to general population. Additionally, male individuals with DS often show infertility, while women tend to experience menopause at an overall younger age than healthy controls. Given the recent outstanding improvements in the care of severe DS-related comorbidities, infant mortality has dramatically decreased, with a current average life expectancy exceeding 60 years. Accordingly, the awareness of the specificities of DS in this field is pivotal to timely detect endocrine dysfunctions and to undertake a prompt dedicated treatment. Notably, best practices for the screening and monitoring of pediatric endocrine disorders in DS are still controversial. In addition, specific guidelines for the management of metabolic issues along the challenging period of transitioning from pediatric to adult health care are lacking. By performing a review of published literature, we highlighted the issues specifically involving children and adolescent with DS, aiming at providing clinicians with a detailed up-to-date overview of the endocrine, metabolic and auxological disorders in this selected population, with an additional focus on the management of patients in the critical phase of the transitioning from childhood to adult care.

Role of long non-coding RNAs in Down syndrome patients: a transcriptome analysis study

Down syndrome (DS) is defined by the presence of a third copy of chromosome 21. Several comorbidities can be found in these patients, such as intellectual disability (ID), muscle weakness, hypotonia, congenital heart disease, and autoimmune diseases. The molecular mechanisms playing a role in the development of such comorbidities are still unclear. The regulation and expression of genes that map to chromosome 21 are dynamic and complex, so it is important to perform global gene expression studies with high statistical power to fully characterize the transcriptome in DS patients. This study was undertaken to evaluate mRNAs and lncRNA expression in patients with DS versus a matched cohort of healthy subjects. RNA sequencing was used to perform this transcriptome study. Differential expression analysis revealed 967 transcripts with padj ≤ 0.05. Among them, 447 transcripts were differentially expressed in patients with DS compared to controls. Particularly, 203 transcripts were down expressed (151 protein-coding mRNAs, 45 lncRNAs, 1 microRNA, 1 mitochondrial tRNA, 1 ribozyme, and 1 small nuclear RNA) and 244 were over expressed (210 protein-coding mRNAs and 34 lncRNAs). Interestingly, deregulated lncRNAs are involved in pathways that play a role in developmental disorders, neurological diseases, DNA replication and repair mechanisms, and cancer development in DS patients. In conclusion, these results suggest a role of lncRNAs in the phenotype of DS patients.

A male Down syndrome with two normal boys: Cytogenetic, paternity and andrological investigations

Down syndrome is the most common autosomal chromosome anomaly with several medical abnormalities and intellectual disability, occurring in about of 1:1,000 to 1:1,100 infants. Many pregnancies in women with Down syndrome produce children both with normal and with trisomy 21, whereas males are infertile. However, Down syndrome males are not always infertile and this is not global. Here we reported a 36-year-old man with proved nonmosaic trisomy 21 fathered two normal boys. Paternity analysis using 26 microsatellite loci confirmed that Down syndrome male is the biological father of his two normal boys. Serum LH, FSH, testosterone and 17-OH progesterone were all in the normal range in this father with Down syndrome. To the best of our knowledge, this is the second report of one man with Down syndrome who has two normal children in the world. The current study not only supports the rare evidence of the fertility of males with Down syndrome but also highlights the caution in advising people responsible for the care of adults with this condition about possible fertility and transmission of sexual diseases as well.

Down syndrome and infertility: what support should we provide?

Down syndrome (DS) is the most common genetic disease at birth; on average, it affects 1 in 700 newborns. The syndrome features cognitive impairment, susceptibility to certain diseases, and (in some cases) congenital malformations. Improvements in medical care for people with DS have led to an increase in life expectancy. Furthermore, the systematic provision of specific support during childhood improves cognitive function and autonomy in adulthood. Consequently, patients and their families are now seeking the same rights as healthy people. Access to procreation is an emerging debate. The presumption of infertility in DS is based on a few old studies. Down syndrome appears to cause spermatogenesis defects in men and premature menopause in women. When assisted reproductive technology makes it possible to solve these problems, the question of fertility in DS must be addressed. Without entering into highly controversial ethical considerations related to parenthood for people with DS, we reviewed the literature on fertility in DS and tried to specify the associated genetic risk.

Birth of a healthy child after preimplantation genetic screening of embryos from sperm of a man with non-mosaic Down syndrome

PURPOSE

The purpose of this study is to present a case of healthy infant born after intracytoplasmic sperm injection-in vitro fertilization (ICSI-IVF) with preimplantation genetic screening (PGS) using sperm from a man with non-mosaic trisomy 21 and a literature review.

MATERIALS AND METHODS

A 26-year-old euploid female and 29-year-old male with non-mosaic trisomy 21 and male factor undergoing ICSI-IVF treatment for primary infertility with embryo biopsy for PGS with comprehensive chromosomal screening (CCS) presented to the Infertility Clinic at Highland Hospital, the Alameda County Medical Center, California, with 6-year history of primary infertility. The outcome measure is a live birth of a healthy child and ploidy status of biopsied blastocysts.

RESULTS

Egg retrieval yielded 33 oocytes, 29 of which underwent ICSI with ejaculated sperm. Twenty-eight 2PN zygotes were cultured, and 13 blastocysts underwent trophectoderm biopsy and vitrification 5 or 6 days after retrieval. CCS analysis revealed that 12 out of 13 (92 %) of blastocysts were euploid and one was a complex abnormal mosaic. Transfer of two grade I hatching blastocysts resulted in a singleton pregnancy with normal prenatal genetic screening and delivery of a healthy male infant at 41 weeks via primary cesarean section for non-reassuring fetal status.

CONCLUSION

This is the first report of a live birth of a healthy child after ICSI-IVF with PGS using ejaculated sperm from a man with non-mosaic trisomy 21 and male factor infertility.

Social conditions for people with Down syndrome: a register-based cohort study in Denmark

Today, most persons with Down syndrome (DS) survive into middle age, but information on their social conditions as adults is limited. We addressed this knowledge gap using data from national registers in Denmark. We identified a national cohort of 1,998 persons with DS who were born between 1968 and 2007 (1,852 with standard trisomy 21, 80 with Robertsonian translocations and 66 with mosaicism) using the Danish Cytogenetic Register. We followed this cohort from 1980 to 2007. Information on social conditions (education, employment, source of income, marital status, etc.) was obtained by linkages to national registers, including the Integrated Database for Longitudinal Labor Market Research. For those aged 18 and older, more than 80% of persons with DS attended 10 years of primary school, with about 2% completing secondary or post-secondary education. About 4% obtained a full-time job, whereas the remaining mainly received public support from the government. Only a few (1-2%) of persons with DS were married or had a child. No significant differences in these social conditions were seen between males and females. More persons with mosaic DS attended secondary or post-secondary education, had a full-time job, were married, or had a child (18%, 28%, 15%, and 7%, respectively), compared with persons with standard DS (1%, 2%, 1%, and 1%, respectively). These data may provide families with better insight into social conditions and society with a better understanding of the social support needed for persons with DS.

Causes of infertility in men with Down syndrome

Men with Down syndrome are considered as infertile although the causes of infertility are not known in detail yet. Although this constitutes a general rule there are three confirmed cases of parenting by fathers with Down syndrome. Many investigators have addressed the causes of infertility and their studies indicate that the causes may be hormonal deficits, morphological alterations of the gonads, abnormal spermatogenesis, psychological and social factors related to the mental retardation. It is obvious that the extra chromosome 21 has a detrimental direct and indirect effect on the reproductive capacity of the affected male patient. But the definite cause of the insufficient and inadequate spermatogenesis remains to be discovered.

Endocrine and musculoskeletal abnormalities in patients with Down syndrome

Down syndrome has a prevalence of one in 500 to one in 1,000 live births and is the most common cause of mental retardation. Most patients are treated in childhood and adolescence for mental or growth retardation. Studies that evaluate bone mass in Down syndrome are limited, and many are small case series in pediatric and adult populations who live either in the community or in residential institutions. Several environmental and hormonal factors contribute to low bone mineral density in such patients. Muscle hypotonia, low amounts of physical activity, poor calcium and vitamin D intakes, hypogonadism, growth retardation and thyroid dysfunction contribute to substantial impairments in skeletal maturation and bone-mass accrual that predispose these patients to fragility fractures. Here, we review indications and limitations of bone-mass measurements in children, summarize the endocrine and skeletal abnormalities in patients presenting with Down syndrome, and review studies that investigate therapeutic strategies for such patients.

Fertility in men with Down syndrome: a case report

OBJECTIVE

To inform clinicians about fertility in males with Down syndrome.

DESIGN

Case report.

SETTING

Medical Genetics Department of a tertiary-care hospital.

PATIENT(S)

A 26-year-old man with confirmed nonmosaic trisomy 21.

INTERVENTION(S)

Karyotype, amniocentesis, paternity testing using microsatellite markers.

MAIN OUTCOME MEASURE(S)

Confirmed paternity in the son of a male with nonmosaic trisomy 21.

RESULT(S)

A male with nonmosaic Down syndrome fathered a normal son, and the paternity was proven by microsatellite marker analysis.

CONCLUSION(S)

Although Down syndrome males have been reported to be infertile, it may not always be true. Infertility in males has been attributed to defective spermatogenesis, but ignorance of the sexual act may be one of the contributing factors. It is important to advise postpubertal Down syndrome males on contraceptive measures.

Impact of trisomy on fertility and meiosis in male mice

BACKGROUND

Chromosomal abnormalities frequently are associated with impairment or arrest of spermatogenesis in mammals but are compatible with fertility in female carriers of the same anomaly. In the case of trisomy, mice have extra genomic DNA as well as the chromosomal abnormality, usually present as an extra, unpaired chromosome. Thus, impairment of spermatogenesis in trisomic males could be due to the presence of extra genomic material (i.e. triplicated genes) or due to the chromosomal abnormality and presence of an unpaired chromosome in meiosis.

METHODS

In this study, fertility and chromosomal pairing configurations during meiotic prophase were analysed in male mice trisomic for different segments of the genome. Four have an extra segmental or tertiary trisomic chromosome--Ts(17(16))65Dn, Ts(10(16))232Dn, Ts(12(17))4Rk and Ts(4(17))2Lws--and one has the triplicated segment attached to another chromosome--Ts(16C-tel)1Cje. Ts(17(16))65Dn and Ts(16C-tel)1Cje have similar gene content triplication and differ primarily in whether the extra DNA is in an extra chromosome or not.

RESULTS

The presence of an intact extra chromosome, rather than trisomy per se, is associated with male sterility. Additionally, sterility is correlated with a high frequency of association of the unpaired chromosome with the XY body, which contains the largely unpaired X and Y chromosomes.

CONCLUSIONS

Intact extra chromosomes disrupt spermatogenesis, and unpaired chromosomes establish a unique chromatin territory within meiotic nuclei.

Evolutionary neuropathology and Down syndrome: An analysis of the etiological and phenotypical characteristics of Down syndrome suggests that it may represent an adaptive response to severe maternal deprivation

This paper will suggest that the Down syndrome phenotype would have been well suited, physiologically, for a deprived environment and that it may represent a predictive, adaptive response to severe maternal deprivation. A trisomy of the 21st chromosome, prior to, or at conception is responsible for Down syndrome and is known to increase in incidence with advanced maternal age. One out of 11 mothers over the age of 50 conceives a Down syndrome baby, compared to one in one thousand at age 30. This article emphasizes that an older mother is more likely to die before she is able to provide the parental investment necessary to produce an ecologically self-sufficient offspring. Prolonged maternal investment is known to be essential for hunter-gatherers to master the skill intensive food procurement techniques that they will need in order to become independent of their mothers. Because Down syndrome individuals are much more likely to be born to older mothers, they must have been routinely deprived of maternal investment in the human environment of evolutionary adaptedness. This consistent paring of maternal deprivation to trisomy 21 conceptions, over time, may have caused natural selection to favor genes responsible for the energy conserving traits seen in modern day Down syndrome. These traits include muscle hypotonia, decreased cerebral metabolism, decreased hippocampal volume, a strong propensity for obesity and growth hormone and thyroid hormone paucity. Such a "thrifty phenotype" may have allowed Down syndrome individuals to become independent of their mothers at a far earlier age and allowed them to forgo the skill intensive ecological niche that non-trisomic humans are phenotypically suited for in order to take up a less cognitively and physically rigorous one.

Sexual health care in persons with intellectual disabilities

In the past, preventive health concerning sexuality of people with intellectual disabilities was addressed through surgical sterilization as part of nationwide eugenic programs in many countries. For more than 30 years now, it has come progressively to light in the scientific literature that, besides major ethical and legal problems, these programs also failed to assess many of the individual's needs in sexual health. The fact that an increasing number of people with intellectual disabilities live in the community rather than in institutions has heightened public awareness that these individuals have sexual expectancies, desires, and needs that must be supported through both education and health services. The emergence of AIDS, including descriptions of cases among people with intellectual disabilities, has further demonstrated that surgical sterilization cannot be considered a global option to achieve preventive sexual health. The aim of this paper is to review scientific studies that have assessed the expectancies and support needs of persons with intellectual disabilities in terms of sexual health. These needs vary widely from one individual to another, according to life milieu, level of disability, and potential comorbidity. From this review, it appears that hygiene management, global gynecological care, and prevention of unplanned pregnancy, sexually transmitted diseases, and abuse have been frequently identified as areas in which the presence of intellectual disability dictates specific support needs. Different approaches that have been evaluated to address these issues will also be discussed.

Intracytoplasmic injection of spermatozoa and spermatogenic cells: its biology and applications in humans and animals

Intracytoplasmic sperm injection (ICSI) has become the method of choice to overcome male infertility when all other forms of assisted fertilization have failed. Animals in which ICSI has produced normal offspring include many species. Success rate with normal spermatozoa is well above 50% in the mouse but ICSI success rates in other animals have been low, ranging from 0.3 to 16.5%. Mouse ICSI revealed that spermatozoa that cannot participate in normal fertilization can produce normal offspring by ICSI, provided their nuclei are genomically intact. Human ICSI using infertile spermatozoa has been highly successful perhaps because of the intrinsic instability of human sperm plasma membrane. The health of children born after ICSI and other assisted fertilization techniques is of major concern. Careful analyses suggest that higher incidences of congenital malformations and/or low birth weights after assisted fertilization are largely attributable to parental genetic background and increased incidence of multiple births, rather than to the techniques of assisted fertilization. Since the physiological and nutritional environments of developing embryos may cause persisting alteration in DNA methylation, extreme caution must be exercised in handling gametes and embryos in vitro. In the mouse, round spermatid injection (ROSI) has been routinely successful but its use in humans is controversial. Whether human ROSI and assisted fertilization involving younger spermatogenic cells are medically safe must be the subject of further investigations.

Sexuality and disease

Disease is commonly associated with sexual dysfunction in both men and women. In many cases, effective treatments are available that can improve libido, erectile dysfunction, and vaginal dryness. Sexual problems in older persons with disease often lead to anxiety, marital discord, and withdrawal. It is the responsibility of all health care professionals to inquire about sexuality in all patients, no matter what the patient's age, and to be aware that frailty [79-81] is not, in itself, a barrier to sexuality. Health professionals need to give education, support, and counseling on sexuality for patients with disease.

[Sexuality in Down syndrome individuals]

OBJECTIVE

To evaluate parents and health professionals' opinions on the sexuality of Down syndrome individuals and to describe how these individuals see their own sexuality.

METHODS

Both quantitative and qualitative analyses have been applied in the study. A total of 809 questionnaires were to parents and health professionals (348). Twelve focal groups' sessions were carried out separately with parents, professionals and DS individuals. Chi-square test was performed in the analysis.

RESULTS

Parents see their children as eternal kids as they are afraid of the utmost outcome of their children's sexual life: unwanted pregnancy, and risk of syndrome recurrence. Health professionals revealed to be unprepared to provide sexual advice for DS individuals and adequate parents' attitude to their children's sexual drive.

CONCLUSIONS

Down syndrome sexuality develops similarly to other individuals, but DS individuals experience restrictions depending on their social context.

Bone mass, gonadal function and biochemical assessment in young men with trisomy 21

OBJECTIVE

The objective of the study was to find out whether biochemical and hormonal profile of sexual function and mineral metabolism are related to low bone mass in young men with Down syndrome.

STUDY DESIGN

Eleven young men with trisomy 21 (mean age 26.45 years) and 12 healthy university students of similar age, participated in the study. The bone mineral density (BMD) of the lumbar vertebrae was measured in posteroanterior (PA) projection. Sexual development was assessed by clinical examination. The levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, dehydroepiandrosterone sulfate (DHEA-S), 17-OH progesterone and parathormone (PTH) were measured accordingly by radioimmunoassay. Serum calcium (Ca) and phosphate (P) as well as fasting urinary Ca and hydroxyproline (OHP) were also measured.

RESULTS

BMD in DS patients was significantly lower (P<0.001) compared to their control counterparts. No significant differences were observed in mean concentrations of FSH, testosterone and DHEA-S, while LH and 17-OH progesterone levels were significantly higher in DS compared to control group (P<0.01 and <0.05, respectively). Serum Ca and P and urine Ca/Creat ratio did not differ between groups. OHP/Creat ratio was significantly higher in DS patients. PTH levels were extremely low (1pmol/l) in two patients.

CONCLUSIONS

The findings of this study show decreased bone mass in subjects with DS. Factors, possibly related to low bone mass, are some degree of hypogonadim, hypotonia, low muscular strength and immobility. The findings suggest further research on the biochemistry and endocrinology of bone metabolism in patients with trisomy 21.

Gonadal function in young women with Down syndrome

OBJECTIVE

Investigations suggest an increased incidence of gonadal dysfunction in patients with Down syndrome. New features, Alzheimer disease and osteoporosis emerge in these individuals. Therefore, hormonal investigation in persons with Down syndrome is pursued.

METHODS

Thirteen females with trisomy 21 (23.65 +/- 3.23 years old) participated in the study. Ultrasound studies were performed to explore the internal genitals. Blood samples were taken for the determination of follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), prolactin (PRL), dehydroepiandrosterone sulfate (DHEA-S), testosterone (T) and 17-hydroxyprogesterone (17-OHP).

RESULTS

The patients were at stage V of sexual development. Ultrasonography demonstrated normal uterine and ovarian size and endometrial thickness as well. The ovaries of all patients contained follicles of normal distribution and various sizes. The mean concentrations of FSH, DHEA-S and E2 were normal. The level of PRL was significantly higher than that of the controls, but within the normal lab range. The levels of LH, T and 17-OHP were significantly elevated, compared to those of the control group (P < 0.05, P < 0.01, P < 0.001, respectively).

CONCLUSIONS

Our data produce new information on the gonadal function of Down syndrome women. Specific studies on pituitary-gonadal and pituitary-adrenal axis function are needed.

Growth and pubertal development in Down syndrome

Growth retardation and gonadal insufficiency are well-known features of Down syndrome. In this longitudinal study, 44 home-reared children and adolescents with Down syndrome, aged 10-24 years, living in the county of Uppsala, were followed yearly. The male patients had a mean final height above that reported previously, and a close correlation between target and final heights was found. The mean final height in the female patients was below that reported earlier. Mean peak height velocities in males and females were 8.5 and 7.3 cm year-1, respectively, significantly lower than in healthy children. The mean ages at peak height velocity were 12.3 and 10.8 years, respectively, indicating early growth spurts. The serum follicle-stimulating hormone concentrations, the small testes and the negative correlation between luteinizing hormone and testicular volume in the males may indicate some primary gonadal insufficiency. For the girls, mean menarcheal age corresponded closely to that of their mothers.