Case report: Whole exome sequencing identified a novel mutation (p.Y301H) of MAF in a Chinese family with congenital cataracts.

Background: Congenital cataracts stand as the primary cause of childhood blindness globally, characterized by clouding of the eye's lens at birth or shortly thereafter. Previous investigations have unveiled that a variant in the V-MAF avian musculoaponeurotic-fibrosarcoma oncogene homolog (MAF) gene can result in Ayme-Gripp syndrome and solitary cataract. Notably, MAF mutations have been infrequently reported in recent years. Methods: In this investigation, we recruited a Chinese family with non-syndromic cataracts. Whole exome sequencing and Sanger sequencing were applied to scrutinize the genetic anomaly within the family. Results: Through whole exome sequencing and subsequent data filtration, a new mutation (NM_005360, c.901T>C/p.Y301H) in the MAF gene was detected. Sanger sequencing validated the presence of this mutation in another affected individual. The p.Y301H mutation, situated in an evolutionarily preserved locus, was not detected in our 200 local control cohorts and various public databases. Additionally, multiple bioinformatic programs predicted that the mutation was deleterious and disrupted the bindings between MAF and its targets. Conclusion: Hence, we have documented a new MAF mutation within a Chinese family exhibiting isolated congenital cataracts. Our study has the potential to broaden the spectrum of MAF mutations, offering insights into the mechanisms underlying cataract formation and facilitating genetic counseling and early diagnosis for congenital cataract patients.

Silencing MYOT Expression May Inhibit Autophagy in Human Skeletal Muscle Cells.

Muscle diseases are closely related to autophagy disorders. Studies of autophagy inhibition indicated the importance of autophagy in muscle regeneration, while activation of autophagy can restore muscle function in some myopathies. Previous studies have revealed that mutations in the MYOT gene may lead to several kinds of hereditary myopathies. However, whether the autophagy played a crucial role in hereditary myopathy caused by MYOT mutations was still not clear. In this study, we established the MYOT knockdown human skeletal muscle cell models (HSkMCs) by small interfering RNA. Real-time PCR and Western blot studies found that the expression of p62 and LC3B-II was decreased dramatically, which suggested that silencing MYOT expression may regulate the autophagy in HSkMCs. Further immunofluorescence study on Ad-mCherry-GFP-LC3B adenovirus transfection and monodansylcadaverine (MDC) staining revealed that knocking down the expression of MYOT may inhibit the autophagy. Next, we used the autophagy inducer Earle's balanced salt solution (EBSS) and late-autophagy inhibitor bafilomycin A1 (BAF A1) to treat the HSkMCs, respectively, and found that silencing MYOT expression can inhibit the activation of autophagy by EBSS and aggravate the inhibition of autophagy by BAF A1. Finally, we also found that silencing MYOT expression can downregulate the expression of ATG7 and ATG5, two important autophagy regulatory molecules. Hence, our study may first reveal that knocking down the expression of MYOT may inhibit the autophagy. Hereditary myopathies caused by MYOT mutations may partly result from the inhibition of autophagy in HSkMCs.

A de novo mutation (p.S1419F) of Retinoic acid induced 1 is responsible for a patient with Smith-Magenis syndrome exhibiting schizophrenia.

Smith-Magenis syndrome (SMS, OMIM# 182290) is a rare congenital disorder which characterized by multiple abnormalities involving in craniofacial, skeletal, otorhinolaryngolocial, neurological, behavioral and others. 17p11.2 microdeletion and RAI1 mutations have been proven to be genetic lesions of this disease. However, the relationship between RAI1 variants and different phenotypes is still unclear. The discoveries of more RAI1 mutations in patients with different phenotypes will help to elucidate the pathogenesis of the RAI1 gene. Here, we describe a young patient with schizophrenia and headache as the main clinical presentation, with SMS-like features including depression, sleep disturbance and pain-free status. Whole exome sequencing and Sanger sequencing suggested that a de novo mutation (NM_030665.3: c.4256C > T/p.S1419F) of RAI1 may be the genetic lesion of the patient. The bioinformatic program predicted that the new mutation (p.S1419F), located in an evolutionarily conserved site of RAI1, was deleterious. Further, western blot analysis suggested that the novel mutation may decrease the protein levels of RAI1 in the patient. Hence, we reported a novel mutation of RAI1 in a patient with SMS, schizophrenia and headache. Our study may expand the spectrum of RAI1 mutations which may further contribute to the mechanisms underlying SMS, schizophrenia and headache.