Ocular albinism with infertility and late‐onset sensorineural hearing loss

Novel mutation leading to splice donor loss in a conserved site of DMD gene causes Duchenne muscular dystrophy with cryptorchidism

BACKGROUND

As one of the most common congenital abnormalities in male births, cryptorchidism has been found to have a polygenic aetiology according to previous studies of common variants. However, little is known about genetic predisposition of rare variants for cryptorchidism, since rare variants have larger effective size on diseases than common variants.

METHODS

In this study, a cohort of 115 Chinese probands with cryptorchidism was analysed using whole-genome sequencing, alongside 19 parental controls and 2136 unaffected men. Additionally, CRISPR-Cas9 editing of a conserved variant was performed in a mouse model, with MRI screening used to observe the phenotype.

RESULTS

In 30 of 115 patients (26.1%), we identified four novel genes (ARSH, DMD, MAGEA4 and SHROOM2) affecting at least five unrelated patients and four known genes (USP9Y, UBA1, BCORL1 and KDM6A) with the candidate rare pathogenic variants affecting at least two cases. Burden tests of rare variants revealed the genome-wide significances for newly identified genes (p<2.5×10-6) under the Bonferroni correction. Surprisingly, novel and known genes were mainly found on X chromosome (seven on X and one on Y) and all rare X-chromosomal segregating variants exhibited a maternal inheritance rather than de novo origin. CRISPR-Cas9 mouse modelling of a splice donor loss variant in DMD (NC_000023.11:g.32454661C>G), which resides in a conserved site across vertebrates, replicated bilateral cryptorchidism phenotypes, confirmed by MRI at 4 and 10 weeks. The movement tests further revealed symptoms of Duchenne muscular dystrophy (DMD) in transgenic mice.

CONCLUSION

Our results revealed the role of the DMD gene mutation in causing cryptorchidism. The results also suggest that maternal-X inheritance of pathogenic defects could have a predominant role in the development of cryptorchidism.

Repair mechanism of Yishen Tongluo formula on mouse sperm DNA fragmentation caused by polystyrene microplastics

CONTEXT

Plastics can break down into millions of microplastic (MPs, < 5 mm) particles in the soil and ocean. These MPs can then affect the function of the reproductive system. There is currently no effective solution to this problem aside from traditional Chinese medicine. We have previously used Yishen Tongluo formula (YSTL) to treat sperm DNA damage caused by some toxic substances.

OBJECTIVE

To investigate the mechanism underlying the repair of mouse sperm DNA fragmentation caused by polystyrene microplastics by YSTL.

MATERIALS AND METHODS

An animal model of polystyrene microplastic (PS-MP)-induced sperm DNA damage was replicated by gavage of SPF ICR (CD1) mice PS-MPs at 1 mg/d and treated with YSTL at 11.89, 23.78 and 47.56 g/kg, respectively, for 60 days. The Sperm DNA fragmentation index (DFI) of each group was detected and compared. The target genes of YSTL identified by transcriptomic and proteomic analyses were validated by qRT-PCR and western blotting.

RESULTS

The DFI of the PS group (20.66%) was significantly higher than that of the control group (4.23%). The medium and high doses of the YSTL group (12.8% and 11.31%) exhibited a significant repairing effect. The most enriched pathway was PI3K/Akt. TBL1X, SPARC, hnRNP0, Map7D1, Eps8 and Mrpl27 were screened and SPARC was validated.

DISCUSSION AND CONCLUSIONS

The precise mechanism by which YSTL inhibits PD-MPs DNA damage may be associated with the PI3K/Akt pathway and SPARC. It provides a new direction for using traditional Chinese medicine to prevent and repair reproductive system injury caused by MPs.

Ocular findings and genomics of X-linked recessive disorders: A review

Advent of new sequencing technologies and modern diagnostic procedures has opened the door for a deeper understanding of disorders about which little was known previously. Discovery of novel genes, new genetic variants in previously known genes and better techniques of functional validation has immensely contributed to unraveling the molecular basis of genetic disorders. Availability of knockout animal models like the zebrafish and gene editing tools like CRISPR-Cas9 has elucidated the function of many new genes and helped us to better understand the functional consequences of various gene defects. This has also led to better diagnosis and therapeutic interventions. In this context, a good body of research work has been done on X-linked recessive disorders with ocular findings. This review will focus on ocular and genetic findings of these rare disorders. To our knowledge, this is the first comprehensive review encompassing ocular and genomic spectrum of X-linked recessive disorders.

Association Between Sensorineural Hearing Loss and Vitiligo: A Nationwide Population-Based Cohort Study

BACKGROUND

Vitiligo is an acquired depigmentation disease of the skin due to melanocyte destruction. A shared pathogenesis affecting melanocytes in the cochlea has been postulated. However, the association between vitiligo and sensorineural hearing loss (SNHL) is unclear.

OBJECTIVE

To identify the association between vitiligo and SNHL.

METHODS

This retrospective, nationwide cohort study included patients with vitiligo and age-, sex-, and comorbidities-matched controls (propensity score matching; 1:4 ratio) from the National Health Insurance Research Database in Taiwan from January 1, 2000 to December 31, 2013.

RESULTS

In total, 13048 patients with vitiligo and 52192 controls were included. SNHL developed in 0.61% patients with vitiligo and 0.29% controls. After adjusting for sex, age, and comorbidities, a significant association between vitiligo and SNHL was found (adjusted hazard ratio, 2.18; 95% CI, 1.66-2.86). The other risk factors for developing SNHL included increased age, male sex, hyperlipidemia, coronary artery disease, and diffuse connective tissue diseases. In subgroup analysis, the association between vitiligo and SNHL remained significant in almost all the subgroups.

CONCLUSION

A 2.2-fold increased risk of developing SNHL was found in patients with vitiligo. Proper referral to otologists for early screening and closer follow-up of SNHL should be considered for patients with vitiligo, especially for patients with older age.

Clinical implications of Y chromosome microdeletions among infertile men

Male factor infertility contributes significantly to couples facing difficulty achieving a pregnancy. Genetic factors, and specifically those related to the Y chromosome, may occur in up to 15% of men with oligozoospermia or azoospermia. A subset of loci within the Y chromosome, known as the azoospermia factors (AZFa, AZFb, and AZFc), have been associated with male infertility. Emerging evidence has demonstrated that microdeletions of at least a subset of these regions may also have impacts on systemic conditions. This review provides a brief review of male infertility and the structure of the Y chromosome, and further highlights the role of Y chromosome microdeletions in male infertility and other systemic disease.

Meta-analysis of 542,934 subjects of European ancestry identifies new genes and mechanisms predisposing to refractive error and myopia

Refractive errors, in particular myopia, are a leading cause of morbidity and disability worldwide. Genetic investigation can improve understanding of the molecular mechanisms that underlie abnormal eye development and impaired vision. We conducted a meta-analysis of genome-wide association studies (GWAS) that involved 542,934 European participants and identified 336 novel genetic loci associated with refractive error. Collectively, all associated genetic variants explain 18.4% of heritability and improve the accuracy of myopia prediction (area under the curve (AUC) = 0.75). Our results suggest that refractive error is genetically heterogeneous, driven by genes that participate in the development of every anatomical component of the eye. In addition, our analyses suggest that genetic factors controlling circadian rhythm and pigmentation are also involved in the development of myopia and refractive error. These results may enable the prediction of refractive error and the development of personalized myopia prevention strategies in the future.