Fertility in men with Down syndrome: a case report

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.

DYRK1A Overexpression in Mice Downregulates the Gonadotropic Axis and Disturbs Early Stages of Spermatogenesis

Down syndrome (DS) is the most common chromosomal disorder. It is responsible for intellectual disability (ID) and several medical conditions. Although men with DS are thought to be infertile, some spontaneous paternities have been reported. The few studies of the mechanism of infertility in men with DS are now dated. Recent research in zebrafish has indicated that overexpression of DYRK1A (the protein primarily responsible for ID in DS) impairs gonadogenesis at the embryonic stage. To better ascertain DYRK1A's role in infertility in DS, we investigated the effect of DYRK1A overexpression in a transgenic mouse model. We found that overexpression of DYRK1A impairs fertility in transgenic male mice. Interestingly, the mechanism in mice differs slightly from that observed in zebrafish but, with disruption of the early stages of spermatogenesis, is similar to that seen in humans. Unexpectedly, we observed hypogonadotropic hypogonadism in the transgenic mice.

NANOS3 downregulation in Down syndrome hiPSCs during primordial germ cell-like cell differentiation

Human infertility is a complex disorder at the genetic, molecular, cellular, organ, and hormonal levels. New developing technology based on the generation of human primordial germ cell-like cells (hPGCLCs) from induced pluripotent stem cells (hiPSCs) might improve understanding of early germ cell development (specification, migration, gametogenesis, and epigenetic reconstitutions), as well as offering a solution for infertility and hereditary disorders. In this study, we differentiated hiPSCs with trisomy 21 into hPGCLCs. In vitro-derived germ cells from hiPSCs with Down syndrome (DS) express hPGCLC core circuitry, EOMES, SOX17, and PRDM14 at relatively low levels. TFAP2C and PRDM1 were expressed and remained elevated, whereas NANOS3 and NANOG were downregulated in BMP4-induced hiPSCs with DS. The low level of NANOG and NANOS3 expression might negatively influence hPGCLC generation in DS hiPSCs. We suggest that DS hPGCLCs could be a suitable model for studying human early germ cell development, the epigenetic and molecular mechanisms of PGC specification and formation, as well as related infertility disorders, such as azoospermia and teratozoospermia.

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.

Detection of a Recurrent TMEM38B Gene Deletion Associated with Recessive Osteogenesis Imperfecta

Osteogenesis imperfecta is a clinically and genetically group of heterogeneous disorders associated with decreased bone density, brittle bones, bone deformity, recurrent fractures, and growth retardation. Osteogenesis imperfecta is commonly associated with mutations of the genes encoding for type I collagen (COL1A1/COL1A2). Mutations in other genes, some associated with type I collagen post-translational processing, have also been identified as the cause of osteogenesis imperfecta. Mutations in the transmembrane protein 38B (TMEM38B) gene have been reported in a rare autosomal recessive form of osteogenesis imperfecta.  TMEM38B encodes TRIC-B - a trimeric intracellular cation channel type B which is essential to modulate intracellular calcium signaling. In this study, we are reporting a case of osteogenesis imperfecta type XIV from a Saudi consanguineous family. Our patient was an eight-month-old child with short limbs, club feet, and lower limb deformities with developmental delay. Radiological findings were consistent with the evidence of osteogenesis imperfecta. There was no evidence of impaired hearing or blue sclera and based on the clinical assessment, we classified our patient as a non-syndromic osteogenesis imperfecta. A pathogenic deletion in the chromosome 9q31.2 region, partially encompassing the TMEM38B gene, was detected using chromosomal microarray analysis. This study expands our knowledge about the rare type of osteogenesis imperfecta in our consanguineous population. Besides, it emphasizes the use of genomic medicine in clinical practices to formulate early interventions to clinically improve the patient’s condition.

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.

Human Dizygotic Twinning: Evolutionary-Based Explanations/Twin Research Reviews: Conjoined Twins in a Triplet Pregnancy; Double Embryo Transfer; Health Anxiety; Delayed Delivery of the Second Twin/In the Media: Digital Marketing Twins; Bereaved Twin at March for Our Lives; Exchange of Places; Football Players Reunite as Patriots

Human twinning poses a conundrum for researchers, given that the female uterus is optimally designed to carry a single fetus. Evolutionary explanations of dizygotic (DZ or fraternal) twinning provide insight and understanding of this reproductive event. This review is followed by summaries of recent twin research and reports concerning twins in a triplet pregnancy, double embryo transfer; a twin study of health anxiety, and delayed delivery of the second twin. Twin events reported in the media include a pair of digital marketing twins, a speech by a bereaved twin at the March for Our Lives in Washington, D.C., twins who exchanged places, and a same-team reunion of twin football players.

Endocrine manifestations of Down syndrome

PURPOSE OF REVIEW

To summarize the recent developments in endocrine disorders associated with Down syndrome.

RECENT FINDINGS

Current research regarding bone health and Down syndrome continues to show an increased prevalence of low bone mass and highlights the importance of considering short stature when interpreting dual energy x-ray absorptiometry. The underlying cause of low bone density is an area of active research and will shape treatment and preventive measures. Risk of thyroid disease is present throughout the life course in individuals with Down syndrome. New approaches and understanding of the pathophysiology and management of subclinical hypothyroidism continue to be explored. Individuals with Down syndrome are also at risk for other autoimmune conditions, with recent research revealing the role of the increased expression of the Autoimmune Regulatory gene on 21st chromosome. Lastly, Down-syndrome-specific growth charts were recently published and provide a better assessment of growth.

SUMMARY

Recent research confirms and expands on the previously known endocrinopathies in Down syndrome and provides more insight into potential underlying mechanisms.

Fetopathological examination for the fetuses with Down syndrome in Tunisia: Epidemiological study and associated malformations

BACKGROUND

For Down syndrome (DS), traditional epidemiological studies to determine the prevalence, cause, and clinical significance of the syndrome have been conducted over the last 100 years. In Tunisia, the current work is the first in-depth study in epidemiology of DS from fetopathological data.

AIM OF THE STUDY

The aim of this epidemiological study was to determine the impact of some feto-maternal characteristics in occurrence of DS and to search the frequency of associated congenital malformations with this syndrome.

METHODS

Our retrospective study was realized for 144 fetuses with DS among 9321 autopsied fetuses in embryo-fetopathological service between 1994 and 2011.

RESULTS

In our study, the majority of mothers (72.91%) were 35 years and older, with a statistically significant difference (p<10^-6, OR=16.7, CI=8.7-32.4). The abnormalities of extremities (31%) were the most common fetal abnormalities followed by facial (23.51%) and digestive abnormalities (19.63%).

CONCLUSION

One of the main conclusions of this research is that the most common risk factor for DS is maternal age. On the other hand, the type and the frequency of associated congenital anomalies with DS are still controversial.

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.

Aneuploidy and skeletal health

The normal human chromosome complement consists of 46 chromosomes comprising 22 morphologically different pairs of autosomes and one pair of sex chromosomes. Variations in either chromosome number and/or structure frequently result in significant mental impairment and/or a variety of other clinical problems, among them, altered bone mass and strength. Chromosomal syndromes associated with specific chromosomal abnormalities are classified as either numerical or structural and may involve more than one chromosome. Aneuploidy refers to the presence of an extra copy of a specific chromosome, or trisomy, as seen in Down's syndrome (trisomy 21), or the absence of a single chromosome, or monosomy, as seen in Turner syndrome (a single X chromosome in females: 45, X). Aneuploidies have diverse phenotypic consequences, ranging from severe mental retardation and developmental abnormalities to increased susceptibility to various neoplasms and premature death. In fact, trisomy 21 is the prototypical aneuploidy in humans, is the most common genetic abnormality associated with longevity, and is one of the most widespread genetic causes of intellectual disability. In this review, the impact of trisomy 21 on the bone mass, architecture, skeletal health, and quality of life of people with Down syndrome will be discussed.

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.

Down syndrome in India--diagnosis, screening, and prenatal diagnosis

Down syndrome (DS) is the most common genetic cause of mental retardation. Clinical manifestations are variable, and children have psychomotor impairment, multiple malformations, and medical conditions. Confirmation of the diagnosis is by karyotype analysis. The cytogenetic abnormality can be classified into pure trisomy 21, translocation, or mosaicism. Risk of recurrence depends on the primary cytogenetic abnormality in the proband. Prenatal screening is by biochemical and ultrasound markers in the first and second trimester. Definitive prenatal diagnosis is by analysis of fetal chromosomes in fetal chorionic villi, amniocytes, or cord blood. A noninvasive test for trisomy 21 in maternal blood has been developed by massively parallel shotgun sequencing. Therapeutic studies in Ts65Dn mice suggest an exciting prospect of improvement of learning ability and memory deficits.

Clinical aspects of testicular microlithiasis in boys: a review

OBJECTIVE

After review of the pediatric literature, we report on the prevalence of testicular microlithiasis and its relation with benign and malign entities. We provide a guideline for the management of boys with testicular microlithiasis.

MATERIALS AND METHODS

The databases searched were Medline, Web of Science, Embase and the Cochrane Library. Data on the rates of testicular microlithiasis were collected and from each study information was extracted on the study population according to country, study design, diagnostic method, type of patient, number of patients, age, associated anomalies, additional diagnostic methods and follow-up information. From the 472 articles, we selected 126 articles as potentially relevant, of which 57 were included.

RESULTS

In asymptomatic boys, the prevalence of testicular microlithiasis is 4.2% and in symptomatic referrals it is 1.6%. The development of a testicular malignancy is occasionally reported after diagnosis of testicular microlithiasis. The management of boys with testicular microlithiasis varies widely. Most authors recommend regular self-examination, and some perform testicular ultrasound and/or screen tumor markers.

CONCLUSION

The prevalence of testicular microlithiasis in boys varies between 1.1% and 4.2%. For follow-up, regular self-examination is advised from the age of 15 years.

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.

Practice guidelines for communicating a prenatal or postnatal diagnosis of Down syndrome: recommendations of the national society of genetic counselors

Down syndrome is one of the most common conditions encountered in the genetics clinic. Due to improvements in healthcare, educational opportunities, and community inclusion over the past 30 years, the life expectancy and quality of life for individuals with Down syndrome have significantly improved. As prenatal screening and diagnostic techniques have become more enhanced and widely available, genetic counselors can expect to frequently provide information and support following a new diagnosis of Down syndrome. This guideline was written for genetic counselors and other healthcare providers regarding the communication of a diagnosis of Down syndrome to ensure that families are consistently given up-to-date and balanced information about the condition, delivered in a supportive and respectful manner.

On the paternal origin of trisomy 21 Down syndrome

BACKGROUND

Down syndrome (DS), characterized by an extra free chromosome 21 is the most common genetic cause for congenital malformations and learning disability. It is well known that the extra chromosome 21 originates from the mother in more than 90% of cases, the incidence increases with maternal age and there is a high recurrence in young women. In a previous report we have presented data to indicate that maternal trisomy 21 (T21) ovarian mosaicism might provide the major causative factor underlying these patterns of DS inheritance. One important outstanding question concerns the reason why the extra chromosome 21 in DS rarely originates from the father, i.e. in less than 10% of T21 DS cases. We here report data indicating that one reason for this parental sex difference is a very much lower degree of fetal testicular in comparison to ovarian T21 mosaicism.

RESULTS

We used fluorescence in situ hybridisation (FISH) with two chromosome 21-specific probes to determine the copy number of chromosome 21 in fetal testicular cell nuclei from four male fetuses, following termination of pregnancy for a non-medical/social reason at gestational age 14-19 weeks. The cells studied were selected on the basis of their morphology alone, pending immunological specification of the relevant cell types. We could not detect any indication of testicular T21 mosaicism in any of these four male fetuses, when analysing at least 2000 cells per case (range 2038-3971, total 11.842). This result is highly statistically significant (p < 0.001) in comparison to the average of 0.54% ovarian T21 mosaicism (range 0.20-0.88%) that we identified in eight female fetuses analysing a total of 12.634 cells, as documented in a previous report in this journal.

CONCLUSION

Based on these observations we suggest that there is a significant sex difference in degrees of fetal germ line T21 mosaicism. Thus, it would appear that most female fetuses are T21 ovarian mosaics, while in sharp contrast most male fetuses may be either very low grade T21 testicular mosaics or they may be non-mosaics. We further propose that this sex difference in germ line T21 mosaicism may explain the much less frequent paternal origin of T21 DS than maternal. The mechanisms underlying the DS cases, where the extra chromosome 21 does originate from the father, remains unknown and further studies in this respect are required.

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.