Bi-allelic variants in DNA mismatch repair proteins MutS Homolog MSH4 and MSH5 cause infertility in both sexes.

STUDY QUESTION: Do bi-allelic variants in the genes encoding the MSH4/MSH5 heterodimer cause male infertility? SUMMARY ANSWER: We detected biallelic, (likely) pathogenic variants in MSH5 (4 men) and MSH4 (3 men) in six azoospermic men, demonstrating that genetic variants in these genes are a relevant cause of male infertility. WHAT IS KNOWN ALREADY: MSH4 and MSH5 form a heterodimer, which is required for prophase of meiosis I. One variant in MSH5 and two variants in MSH4 have been described as causal for premature ovarian insufficiency (POI) in a total of five women, resulting in infertility. Recently, pathogenic variants in MSH4 have been reported in infertile men. So far, no pathogenic variants in MSH5 had been described in males. STUDY DESIGN, SIZE, DURATION: We utilized exome data from 1305 men included in the Male Reproductive Genomics (MERGE) study, including 90 males with meiotic arrest (MeiA). Independently, exome sequencing was performed in a man with MeiA from a large consanguineous family. PARTICIPANTS/MATERIALS, SETTING, METHODS: Assuming an autosomal-recessive mode of inheritance, we screened the exome data for rare, biallelic coding variants in MSH4 and MSH5. If possible, segregation analysis in the patients' families was performed. The functional consequences of identified loss-of-function (LoF) variants in MSH5 were studied using heterologous expression of the MSH5 protein in HEK293T cells. The point of arrest during meiosis was determined by γH2AX staining. MAIN RESULTS AND THE ROLE OF CHANCE: We report for the first time (likely) pathogenic, homozygous variants in MSH5 causing infertility in 2 out of 90 men with MeiA and overall in 4 out of 902 azoospermic men. Additionally, we detected biallelic variants in MSH4 in two men with MeiA and in the sister of one proband with POI. γH2AX staining revealed an arrest in early prophase of meiosis I in individuals with pathogenic MSH4 or MSH5 variants. Heterologous in vitro expression of the detected LoF variants in MSH5 showed that the variant p.(Ala620GlnTer9) resulted in MSH5 protein truncation and the variant p.(Ser26GlnfsTer42) resulted in a complete loss of MSH5. LARGE SCALE DATA: All variants have been submitted to ClinVar (SCV001468891-SCV001468896 and SCV001591030) and can also be accessed in the Male Fertility Gene Atlas (MFGA). LIMITATIONS, REASONS FOR CAUTION: By selecting for variants in MSH4 and MSH5, we were able to determine the cause of infertility in six men and one woman, leaving most of the examined individuals without a causal diagnosis. WIDER IMPLICATIONS OF THE FINDINGS: Our findings have diagnostic value by increasing the number of genes associated with non-obstructive azoospermia with high clinical validity. The analysis of such genes has prognostic consequences for assessing whether men with azoospermia would benefit from a testicular biopsy. We also provide further evidence that MeiA in men and POI in women share the same genetic causes. STUDY FUNDING/COMPETING INTEREST(S): This study was carried out within the frame of the German Research Foundation sponsored Clinical Research Unit 'Male Germ Cells: from Genes to Function' (DFG, CRU326), and supported by institutional funding of the Research Institute Amsterdam Reproduction and Development and funds from the LucaBella Foundation. The authors declare no conflict of interest.

Development, behaviour and sensory processing in Marshall-Smith syndrome and Malan syndrome: phenotype comparison in two related syndromes.

BACKGROUND: Ultrarare Marshall-Smith and Malan syndromes, caused by changes of the gene nuclear factor I X (NFIX), are characterised by intellectual disability (ID) and behavioural problems, although questions remain. Here, development and behaviour are studied and compared in a cross-sectional study, and results are presented with genetic findings. METHODS: Behavioural phenotypes are compared of eight individuals with Marshall-Smith syndrome (three male individuals) and seven with Malan syndrome (four male individuals). Long-term follow-up assessment of cognition and adaptive behaviour was possible in three individuals with Marshall-Smith syndrome. RESULTS: Marshall-Smith syndrome individuals have more severe ID, less adaptive behaviour, more impaired speech and less reciprocal interaction compared with individuals with Malan syndrome. Sensory processing difficulties occur in both syndromes. Follow-up measurement of cognition and adaptive behaviour in Marshall-Smith syndrome shows different individual learning curves over time. CONCLUSIONS: Results show significant between and within syndrome variability. Different NFIX variants underlie distinct clinical phenotypes leading to separate entities. Cognitive, adaptive and sensory impairments are common in both syndromes and increase the risk of challenging behaviour. This study highlights the value of considering behaviour within developmental and environmental context. To improve quality of life, adaptations to environment and treatment are suggested to create a better person-environment fit.

Audit of 10 years of referrals for fetal echocardiography.

OBJECTIVES: To evaluate trends over time, indications, diagnoses, noncardiac defects and outcome of fetuses referred for tertiary level echocardiography. METHODS: Retrospective study of fetal echocardiograms performed between April 1999 and 2009. RESULTS: Of the 623 fetuses included, 301 (48%) had cardiac pathology. Congenital heart defects (CHDs) were found in 243/301 (81%), mostly in the severe spectrum. Of the fetuses with CHDs, 26% (63/243) had chromosomal anomalies. The chromosomally normal fetuses with CHDs had a mortality rate of 43% (77/180) and 23% (41/180) had extra-cardiac anomalies. The termination of pregnancy (TOP) rate for all cardiac pathology was 24.9% (75/301) and for CHDs 29.6% (72/243). The TOP rates for CHDs diagnosed before 19 and 24 weeks gestation were 61% (28/46) and 44% (68/155), respectively. An increase in referrals followed the introduction of a national screening program, (nuchal translucency (NT) and routine structural ultrasound screening). The main referral indication was an increased NT (>95th percentile; 32% of cases). CHDs were found in 81/239 (34%) fetuses with an increased NT. CONCLUSIONS: Referral indications for fetal echocardiography were appropriate (almost 50% had cardiac pathology). The mortality was high. Fetal outcome and TOP decisions correlated with CHD severity and presence of noncardiac defects. An increased NT is a strong marker for CHDs.

Targeted ultrasound examination and DNA testing for Noonan syndrome, in fetuses with increased nuchal translucency and normal karyotype.

OBJECTIVE: To define sonographic criteria that may improve the prenatal diagnosis of Noonan syndrome by targeted DNA testing. METHODS: We searched our Fetal Medicine Unit records for all cases with a final diagnosis of Noonan syndrome. A literature review was undertaken to identify the sonographic features of Noonan syndrome fetuses. Information was pooled to define the most common features. RESULTS: In our database, we identified three cases of Noonan syndrome. The diagnosis was suspected prenatally in two of them. Thirty-nine cases were identified in the literature. In the presented cases we show that suspicion of Noonan syndrome should arise when, after an increased nuchal translucency, ultrasound investigation in the second trimester shows a persistant nuchal fold (NF) or cystic hygroma in combination with at least one of the following features: hydrops fetalis, pleural effusion, cardiac anomalies, polyhydramnios or specific facial abnormalities. CONCLUSION: Prenatal ultrasound findings in Noonan syndrome can be subtle and aspecific, but when specific characteristics are present additional targeted DNA analysis is indicated.

Characteristics and outcome and the omphalocele circumference/abdominal circumference ratio in prenatally diagnosed fetal omphalocele.

OBJECTIVE: To evaluate the outcome of fetuses with prenatally diagnosed omphalocele and to investigate the predictive value of the omphalocele circumference/abdominal circumference (OC/AC) ratio - a measure for the relative size of the omphalocele. MATERIALS AND METHODS: This study includes all fetuses prenatally diagnosed with omphalocele at our centre between 1995 and 2007. Medical records and footage of ultrasound examinations were reviewed. Omphalocele was classified in four groups: isolated, chromosomal, syndromic, and multiple anomalies. RESULTS: Eighty-eight cases were identified: 21 (24%) were isolated and 67 had additional structural anomalies. Of the 44 fetuses (50%) with chromosomal anomalies, 2 had omphalocele as a solitary finding. Fifty-three pregnancies (60%) were terminated because of the size of the lesion or associated structural or chromosomal anomalies. Twenty-one cases resulted in a live birth, of which 17 were vaginal deliveries (81%, all uncomplicated) including 3 cases of giant omphalocele (≥5 cm). The OC/AC ratio was found predictive for herniation of the liver, respiratory insufficiency and type of surgical reconstruction. Currently, 12/88 fetuses (14%) are alive and well, including 2 infants with multiple anomalies. CONCLUSION: Identification of omphalocele should arouse suspicion of genetic abnormalities, even in cases that appear isolated. The OC/AC ratio may influence counselling regarding the postnatal course.

Structural heart defects associated with an increased nuchal translucency: 9 years experience in a referral centre.

OBJECTIVE: To investigate the congenital heart disease (CHD) found in association with an increased nuchal translucency (NT) at 11-14 weeks of gestation in chromosomally normal and abnormal fetuses. METHODS: Patients referred from January 1998 until May 2007 with an increased NT (> or = 95th percentile) where CHD was diagnosed were included. Chromosome analysis, fetal and postnatal echocardiography were performed. A postmortem examination followed pregnancy termination when possible. RESULTS: Major CHD was identified in 68 of 967 fetuses with an increased NT (median NT 4.8 mm, range 2.5-22 mm). Major CHD was found in 34 of 693 fetuses (4.9%) with a normal karyotype and increased NT (median 5.2 mm, range 2.5-9.6 mm). CHD frequency increased from 1.9%, with NT between 2.5 and 3.5 mm, to 27.7% when NT was > or = 6.5 mm. Septal defects predominated (20%) when NT was < or = 3.5 mm. With NT > 3.5 mm an equal distribution of CHD types was seen. Major CHD was identified in 34 of the 274 fetuses with an abnormal karyotype and increased NT (median 4.2 mm, range 2.5-22 mm). CONCLUSIONS: A variety of CHD is associated with an increased NT in the first trimester of pregnancy. Conotruncal defects, branchial arch derivative defects, left and right obstructive lesions (inflow and outflow) and shunts were seen.