Analysis of 4 children with DYNC1H1 gene related spinal muscular atrophy with lower extremity predominant 1 / 中华儿科杂志

Objective: To investigate the clinical features and gene variation characteristics of children with dynein cytoplasmic 1 heavy chain 1 (DYNC1H1) gene associated spinal muscular atrophy with lower extremity predominant (SMALED) 1. Methods: The clinical data of 4 SMALED1 children admitted to Peking University First Hospital from December 2018 to May 2021, who were found to have pathogenic variation of DYNC1H1 gene through genetic testing, except for other genes known to be related to motor retardation, were retrospectively summarized to analyze the phenotype and genotype characteristics. Results: There were 3 males and 1 female. The age of onset was 1 year, 1 day, 1 day and 4 months, respectively. The age of diagnosis was 4 years and 10 months, 9 months, 5 years and 9 months, and 3 years and 1 month, respectively. The clinical manifestations were muscle weakness and muscular atrophy of lower limbs, 2 cases with foot deformity, 1 case with early non progressive joint contracture, 1 case with hip dislocation and 1 case with mental retardation. De novo heterozygous missense variations in DYNC1H1 gene were found in all 4 children. According to the rating of American College of medical genetics and genomics, they were all possible pathogenic and pathogenic variations, with p.R598C, p.P776L, p.Y1109D variations had been reported, and p.I1086R variation had not been reported. Conclusions: For those with unexplained lower limb muscle weakness, muscle atrophy, joint contracture and foot deformity, upper limb motor ability related retention, with or without mental retardation, as well as the motor ability progresses slowly, it is necessary to consider the possibility of SMALED1 and the detection of DYNC1H1 gene when necessary.

Clinical feature and pathogenic analysis of a fetus with split hand-foot malformation / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical feature of a fetus with split hand-foot malformation (SHFM) and to explore its etiology.@*METHODS@#Ultrasonographic finding of the fetus and X-ray examination of the abortus were reviewed. Genomic copy number variations (CNVs) of the fetus was analyzed by next-generation sequencing (NGS). Its parents were subjected to chromosomal karyotyping, NGS and fluorescence in situ hybridization (FISH) assays. Real-time fluorescence quantitative PCR was used to measure the expression of genes from the region containing abnormal CNVs.@*RESULTS@#Ultrasonography and X-ray revealed that the right hand and both feet of the fetus were in a V-shape, which was suggestive of SFHM. The results of NGS revealed that the fetus has carried a 0.36 Mb deletion at 7q21.3 region. FISH and NGS analysis of both parents were normal. Real-time fluorescence quantitative PCR confirmed that the fetus carried a single copy of DYNC1I1 gene, while the copy numbers of SEM1, DLX5 and DLX6 genes were normal.@*CONCLUSION@#The 7q21.3 microdeletion probably underlies the SHFM of the fetus, which has a de novo origin.

Genetic genes associated with oligospermia, asthenospermia and teratospermia: Advances in studies / 中华男科学杂志

Approximately 2,300 genes are found to be associated with spermiogenesis and their expressions play important roles in the regulation of spermiogenesis. In recent years, more and more attention has been focused on the studies of the genes associated with oligospermia, asthenospermia and teratospermia and their molecular mechanisms. Some genes, such as GSTM1, DNMT3L, and CYP1A1, have been shown to be potentially associated with oligospermia; some, such as CATSPER1, CRISP2, SEPT4, TCTE3, TEKT4, and DNAH1, with asthenospermia; and still others, such as DPY19L2 and AURKC, with teratospermia. These findings have provided a molecular basis for the studies of the pathogenesis of oligospermia, asthenospermia and teratospermia, as well as a new approach to the exploration of new diagnostic and therapeutic techniques.

Cellular model of neuronal atrophy induced by DYNC1I1 deficiency reveals protective roles of RAS-RAF-MEK signaling

Neuronal atrophy is a common pathological feature occurred in aging and neurodegenerative diseases. A variety of abnormalities including motor protein malfunction and mitochondrial dysfunction contribute to the loss of neuronal architecture; however, less is known about the intracellular signaling pathways that can protect against or delay this pathogenic process. Here, we show that the DYNC1I1 deficiency, a neuron-specific dynein intermediate chain, causes neuronal atrophy in primary hippocampal neurons. With this cellular model, we are able to find that activation of RAS-RAF-MEK signaling protects against neuronal atrophy induced by DYNC1I1 deficiency, which relies on MEK-dependent autophagy in neuron. Moreover, we further reveal that BRAF also protects against neuronal atrophy induced by mitochondrial impairment. These findings demonstrate protective roles of the RAS-RAF-MEK axis against neuronal atrophy, and imply a new therapeutic target for clinical intervention.

N-acetyl-D-glucosamine kinase interacts with dynein light-chain roadblock type 1 at Golgi outposts in neuronal dendritic branch points

N-acetylglucosamine kinase (GlcNAc kinase or NAGK) is a ubiquitously expressed enzyme in mammalian cells. Recent studies have shown that NAGK has an essential structural, non-enzymatic role in the upregulation of dendritogenesis. In this study, we conducted yeast two-hybrid screening to search for NAGK-binding proteins and found a specific interaction between NAGK and dynein light-chain roadblock type 1 (DYNLRB1). Immunocytochemistry (ICC) on hippocampal neurons using antibodies against NAGK and DYNLRB1 or dynein heavy chain showed some colocalization, which was increased by treating the live cells with a crosslinker. A proximity ligation assay (PLA) of NAGK-dynein followed by tubulin ICC showed the localization of PLA signals on microtubule fibers at dendritic branch points. NAGK-dynein PLA combined with Golgi ICC showed the colocalization of PLA signals with somal Golgi facing the apical dendrite and with Golgi outposts in dendritic branch points and distensions. NAGK-Golgi PLA followed by tubulin or DYNLRB1 ICC showed that PLA signals colocalize with DYNLRB1 at dendritic branch points and at somal Golgi, indicating a tripartite interaction between NAGK, dynein and Golgi. Finally, the ectopic introduction of a small peptide derived from the C-terminal amino acids 74-96 of DYNLRB1 resulted in the stunting of hippocampal neuron dendrites in culture. Our data indicate that the NAGK-dynein-Golgi tripartite interaction at dendritic branch points functions to regulate dendritic growth and/or branching.