Maternal age and the risk of fetal aneuploidy: A nationwide cohort study of more than 500 000 singleton pregnancies in Denmark from 2008 to 2017

INTRODUCTION

In this register-based study of pregnancies in Denmark, we assessed the associations between maternal age and the risk of fetal aneuploidies (trisomy 21, trisomy 18, trisomy 13, triploidy, monosomy X and other sex chromosome aberrations). Additionally, we aimed to disentangle the maternal age-related effect on fetal aneuploidies by cases with translocation trisomies and mosaicisms.

MATERIAL AND METHODS

We followed a nationwide cohort of 542 375 singleton-pregnant women attending first trimester screening in Denmark between 2008 and 2017 until delivery, miscarriage or termination of pregnancy. We used six maternal age categories and retrieved information on genetically confirmed aneuploidies of the fetus and infant from the national cytogenetic register.

RESULTS

We confirmed the known associations between advanced maternal age and higher risk of trisomy 21, 18, 13 and other sex chromosome aberrations, especially in women aged ≥35 years, whereas we found no age-related associations with triploidy or monosomy X. Cases with translocation trisomies and mosaicisms did not influence the overall reported association between maternal age and aneuploidies.

CONCLUSION

This study provides insight into the accurate risk of fetal aneuploidies that pregnant women of advanced ages encounter.

45,X/46,XY Mosaicism in an 18-year-old Girl with Primary Amenorrhea : A Case Report

45,X/46,XY mosaicism is a rare disorder with a wide heterogeneity in its manifestations. An 18-year-old girl was referred to the endocrine clinic for investigation of her primary amenorrhea. Clinical examination was unremarkable. Hormonal profile was consistent with primary ovarian insufficiency and human chorionic gonadotropin (hCG) stimulation did not show evidence of active testicular tissue. Karyotyping studies by G-banding revealed a 45,X/46,XY karyotype. She was diagnosed with mosaic Turner syndrome with Y chromosomal material and investigation was performed to identify the presence of male gonads due to the risk of gonadal malignancy. Magnetic resonance imaging (MRI) of the pelvis did not show evidence of gonads. Laparoscopic exploration was proposed but the patient and parents refused opting for conservative management. This case highlights the challenges in the management of this rare condition.

Genetic disorders and male infertility

Background

At present, one out of six couples is infertile, and in 50% of cases, infertility is attributed to male infertility factors. Genetic abnormalities are found in 10%-20% of patients showing severe spermatogenesis disorders, including non-obstructive azoospermia.

Methods

Literatures covering the relationship between male infertility and genetic disorders or chromosomal abnormalities were studied and summarized.

Main findings Results

Genetic disorders, including Klinefelter syndrome, balanced reciprocal translocation, Robertsonian translocation, structural abnormalities in Y chromosome, XX male, azoospermic factor (AZF) deletions, and congenital bilateral absence of vas deferens were summarized and discussed from a practical point of view. Among them, understanding on AZF deletions significantly changed owing to advanced elucidation of their pathogenesis. Due to its technical progress, AZF deletion test can reveal their delicate variations and predict the condition of spermatogenesis. Thirty-nine candidate genes possibly responsible for azoospermia have been identified in the last 10 years owing to the advances in genome sequencing technologies.

Conclusion

Genetic testing for chromosomes and AZF deletions should be examined in cases of severe oligozoospermia and azoospermia. Genetic counseling should be offered before and after genetic testing.

[Examination of sex chromosome abnormalities in childhood]

INTRODUCTION

Early diagnosis of sex chromosome abnormalities is important because of prevention, family planning and optimal therapy.

AIM

Investigation of the relationship between phenotype, age at time of diagnosis and therapeutic options in sex chromosome aberrations.

METHOD

Processing data of 51 children with sex chromosome abnormalities who were diagnosed between 2009 and 2014 and examined at the 2nd. Department of Pediatrics, Semmelweis University, by the methods of anamnesis, family tree analysis, physical examination, karyotype analysis and fluorescent in situ hybridisation.

RESULTS

41% of the patients were diagnosed with Turner-, 18% with Klinefelter-, 10% with double-Y-, 6% with triple- and poly-X-syndrome, 19% with other gonadal dysgenesis and 6% with other abnormality. The average age at diagnosis: Turner- and Klinefelter-syndrome 10 years, other gonadal dysgenesis 9 years, 46,XX,t(X;10) 17 years, other abnormalities 1-2 years.

CONCLUSIONS

Numerical aberrations of the sex chromosomes are more common than structural aberrations. Klinefelter-, triple- and poly-X-syndromes are underdiagnosed in childhood. Early diagnosis of Turner-syndrome and other gonadal dysgenesis is necessary to optimise therapy and prevent associated diseases. This can be achieved by modern prenatal diagnostic methods and targeted activity of family pediatricians. Orv Hetil. 2018; 159(27): 1121-1128.

Clinical and cytogenetic features of 516 patients with suspected Turner syndrome - a single-center experience

BACKGROUND

Clinical suspicion of Turner syndrome (TS) may be challenging. Short stature and absent puberty are not mandatory and the dysmorphic picture is widely variable. The aim of the study was to describe a representative sample of patients with suspected TS in a single center and to verify which set of features may help discriminate those with TS.

METHODS

This was a retrospective study of patients with suspected TS evaluated between 1989 and 2012 with the same clinical and cytogenetic protocols. Data regarding reason for referral, age and height at diagnosis, birth data, pubertal features and dysmorphisms were analyzed.

RESULTS

TS was diagnosed in 36% of 516 patients; structural chromosome anomalies predominated (42%). Short stature was the main reason for referral of patients with and without TS. The mean age of patients at first visit, with TS or without TS was similar (11.89 and 11.35 years, respectively), however, infants and adolescents predominated in the TS group. The mean full-term birth weight was lower in patients with TS as well as height at diagnosis, but normal height z-score was found in 17% of patients. Spontaneous puberty occurred in 30% of TS patients aged 13 years or more, but most had pubertal delay. Residual lymphedema, webbed neck, cubitus valgus, hyperconvex nails, shield chest, abnormal nipples, pigmented nevi, short fourth metacarpal and shorter height were the best discriminators for girls with TS.

CONCLUSIONS

Though short stature, pubertal delay and typical stigmata should prompt investigation of TS, lack of one of these features should not exclude this hypothesis. Dysmorphisms other than those considered "typical" should be sought on physical examination.