Objective:To investigate the steady-state mechanism of interconversion between the SMN1 and SMN2 genes in a normal population. Methods:Fluorescence PCR capillary electrophoresis was employed to assess gene conversion and copy number variation of SMN1 and SMN2 in a cohort of 1, 133 healthy individuals (including 256 males and 877 females) recruited between 2019 and 2023. This study was approved by the Ethics Committee of Henan Provincial People′s Hospital (Ethics No.: 2019-134). Results:No significant gender difference was observed in the single copy carrying rate of SMN1. The probability of conversion from SMN1 to SMN2 was determined to be 3.2% for females, 2.7% for males, and 3.1% for the overall population. The probability of conversion from SMN2 to SMN1 was found to be 5.5% for females, 6.3% for males, and 5.6% for the overall population. No statistically significant difference was found in the conversion probability between different genders ( P>0.05). Among the 99 cases of gene conversion, the SMN1 gene predominantly exhibited a copy number of 2 (97.0%), with the remainder having 3 copies (3%). The SMN2 gene primarily showed a copy number of 2 (72.7%), with the rest having 1 copy (27.3%). Conclusion:Gene conversion tends to normalize the copy numbers of both SMN1 and SMN2 genes towards 2. However, SMN1 exhibited a higher priority over SMN2, causing the copy numbers approaching two.

OBJECTIVE: To investigate the steady-state mechanism of interconversion between the SMN1 and SMN2 genes in a normal population. METHODS: Fluorescence PCR capillary electrophoresis was employed to assess gene conversion and copy number variation of SMN1 and SMN2 in a cohort of 1,133 healthy individuals (including 256 males and 877 females) recruited between 2019 and 2023. This study was approved by the Ethics Committee of Henan Provincial People's Hospital (Ethics No.: 2019-134). RESULTS: No significant gender difference was observed in the single copy carrying rate of SMN1. The probability of conversion from SMN1 to SMN2 was determined to be 3.2% for females, 2.7% for males, and 3.1% for the overall population. The probability of conversion from SMN2 to SMN1 was found to be 5.5% for females, 6.3% for males, and 5.6% for the overall population. No statistically significant difference was found in the conversion probability between different genders (P > 0.05). Among the 99 cases of gene conversion, the SMN1 gene predominantly exhibited a copy number of 2 (97.0%), with the remainder having 3 copies (3%). The SMN2 gene primarily showed a copy number of 2 (72.7%), with the rest having 1 copy (27.3%). CONCLUSION Gene conversion tends to normalize the copy numbers of both SMN1 and SMN2 genes towards 2. However, SMN1 exhibited a higher priority over SMN2, causing the copy numbers approaching two.
Humans ; Male ; Female ; Survival of Motor Neuron 2 Protein/genetics* ; Survival of Motor Neuron 1 Protein/genetics* ; Gene Conversion ; DNA Copy Number Variations/genetics* ; Adult ; Middle Aged ; Gene Dosage

OBJECTIVE: To analyze a Chinese pedigree affected with Non-syndromic autosomal recessive deafness type 12 (NFNB12), validate the function of candidate variants, and explore the underlying mechanisms. METHODS: A NFNB12 pedigree presented at Henan Provincial People's Hospital in February 2023 was selected as the study subject. Whole exome sequencing (WES) was carried out, and candidate variant was verified by Sanger sequencing of the pedigree members. Reverse transcription polymerase chain reaction (RT-PCR) was used to determine the level of mRNA transcription in the peripheral blood samples from the pedigree members, and protein expression was evaluated with Western blotting assay. This study was approved by Medical Ethics Committee of Henan Provincial People's Hospital (Ethics No.: 2019-134). RESULTS: WES analysis revealed that the proband has harbored homozygous c.6688delG (p.Ala2230Profs*4) variant of the CDH23 gene, for which both parents were identified as heterozygous carriers. RT-PCR analysis demonstrated the sole presence of the variant mRNA in the proband, and both the variant and wild-type mRNAs in both parents. Furthermore, Western blotting analysis indicated that the proband had exclusively expressed the truncated CDH23 protein, while both the normal and truncated forms of the protein were noted in her parents. CONCLUSION The c.6688delG (p.Ala2230Profs*4) variant of the CDH23 gene probably underlay the pathogenesis of NFNB12 in this pedigree. The loss of function of the CDH23 gene resulting from this variant is not related with nonsense-mediated mRNA decay, but rather production of a truncated protein. Above finding has not only enriched the mutational spectrum of the CDH23 gene and offered a method for investigating the function of its variants using peripheral blood samples, but also delineated the molecular basis for the loss of function, which has provided crucial evidence for genetic counseling and prenatal diagnosis for this family.
Humans ; Pedigree ; Male ; Female ; Asian People/genetics* ; Cadherins/genetics* ; Exome Sequencing ; Deafness/genetics* ; Mutation ; China ; Adult ; Cadherin Related Proteins ; Hearing Loss, Sensorineural/genetics* ; East Asian People

Objective:To investigate the steady-state mechanism of interconversion between the SMN1 and SMN2 genes in a normal population. Methods:Fluorescence PCR capillary electrophoresis was employed to assess gene conversion and copy number variation of SMN1 and SMN2 in a cohort of 1, 133 healthy individuals (including 256 males and 877 females) recruited between 2019 and 2023. This study was approved by the Ethics Committee of Henan Provincial People′s Hospital (Ethics No.: 2019-134). Results:No significant gender difference was observed in the single copy carrying rate of SMN1. The probability of conversion from SMN1 to SMN2 was determined to be 3.2% for females, 2.7% for males, and 3.1% for the overall population. The probability of conversion from SMN2 to SMN1 was found to be 5.5% for females, 6.3% for males, and 5.6% for the overall population. No statistically significant difference was found in the conversion probability between different genders ( P>0.05). Among the 99 cases of gene conversion, the SMN1 gene predominantly exhibited a copy number of 2 (97.0%), with the remainder having 3 copies (3%). The SMN2 gene primarily showed a copy number of 2 (72.7%), with the rest having 1 copy (27.3%). Conclusion:Gene conversion tends to normalize the copy numbers of both SMN1 and SMN2 genes towards 2. However, SMN1 exhibited a higher priority over SMN2, causing the copy numbers approaching two.

As the most common chromosomal disorder compatible to life, Down syndrome (DS) is caused by an extra copy of chromosome 21. Almost all DS patients have cognitive dysfunction. Therefore, it is important to study the underlying pathogenetic mechanism to elucidate its molecular basis. This article has provided a review for the molecular mechanisms of NRIP1 and DYRK1A genes, which have been closely associated with the cognitive dysfunctions of DS patients. It has also summarized the research progress on the mechanism of DS and development of new therapeutic strategies based on such studies, with an aim to provide insights into the prevention and treatment for the cognitive dysfunctions in DS patients.

As the most common chromosomal disorder compatible to life, Down syndrome (DS) is caused by an extra copy of chromosome 21. Almost all DS patients have cognitive dysfunction. Therefore, it is important to study the underlying pathogenetic mechanism to elucidate its molecular basis. This article has provided a review for the molecular mechanisms of NRIP1 and DYRK1A genes, which have been closely associated with the cognitive dysfunctions of DS patients. It has also summarized the research progress on the mechanism of DS and development of new therapeutic strategies based on such studies, with an aim to provide insights into the prevention and treatment for the cognitive dysfunctions in DS patients.
Down Syndrome/psychology* ; Humans ; Protein-Tyrosine Kinases/genetics* ; Dyrk Kinases ; Protein Serine-Threonine Kinases/genetics* ; Cognition Disorders/etiology*

Objective:To explore the value of whole exome sequencing for the inferential analysis of recessive genetic disease carrier status for couples with a child died of Primary immunodeficiency (PID).Methods:Clinical data was collected from four couples with a childbearing history of PID who had sought genetic counseling and undergone genetic testing at Henan Provincial People′s Hospital from February 2017 to December 2021. Whole exome sequencing (WES) was performed on both partners of each couple, and candidate variants were validated by Sanger sequencing and fluorescent quantitative PCR. Prenatal diagnosis was conducted on fetuses of these couples after confirming the variants.Results:A total of six variants were detected in four genes including IL2RG, BTK, CYBB, and DUOX2. Among these, the c.1265G>A and c.3329G>A variants of the DUOX2 gene and the c. 676C>T variant of the IL2RG gene were previously known as pathogenic variants. On the other hand, the Exon5_8del variant of the IL2RG gene, the c. 184_185delAC variant of the BTK gene, and the c. 472A>T variant of the CYBB gene were unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics, the IL2RG: Exon5_8del, BTK: c. 184_185delAC and CYBB: c. 472A>T variants were classified as likely pathogenic (PVS1+ PM2_Supporting+ PP4).Prenatal diagnosis was conducted for three couples during their subsequent pregnancies, and the results revealed that the fetuses had the wild-type genotypes at the c. 184_185 position of the BTK gene, the c. 472 position of the CYBB gene, and the c. 676 position of the IL2RG gene. Follow-up examinations one year after birth has found no abnormality in the infants. Conclusion:WES is an important tool to infer and analyze the carryier status for couples who had given births to children died of PID and improve the positive detection rate.

Objective:To analyze the clinical features and genetic etiology of 17 Chinese pedigrees affected with X-linked intellectual disability (XLID).Methods:Seventeen pedigrees affected with unexplained intellectual disability which had presented at Henan Provincial People′s Hospital from May 2021 to May 2023 were selected as the study subjects. Clinical data of the probands and their pedigree members were collected. Trio-whole exome sequencing (Trio-WES), Sanger sequencing and X chromosome inactivation (XCI) analysis were carried out. Pathogenicity of candidate variants was predicted based on the guidelines from the American College of Medical Genetics and Genomics and co-segregation analysis.Results:The 17 probands, including 9 males and 8 females with an age ranging from 0.6 to 8 years old, had all shown mental retardation and developmental delay. Fourteen variants were detected by genetic testing, which included 4 pathogenic variants ( MECP2: c. 502C>T, MECP2: c. 916C>T/c.806delG, IQSEC2: c.1417G>T), 4 likely pathogenic variants ( MECP2: c. 1157_1197del/c.925C>T, KDM5C: c. 2128A>T, SLC6A8: c. 1631C>T) and 6 variants of uncertain significance ( KLHL15: c. 26G>C, PAK3: c. 970A>G/c.1520G>A, GRIA3: c. 2153C>G, TAF1: c. 2233T>G, HUWE1: c. 10301T>A). The PAK3: c.970A>G, GRIA3: c. 2153C>G and TAF1: c. 2233T>G variants were considered as the genetic etiology for pedigrees 12, 14 and 15 by co-segregation analysis, respectively. The proband of pedigree 13 was found to have non-random XCI (81: 19). Therefore, the PAK3: c. 1520G>A variant may underlie its pathogenesis. Conclusion:Trio-WES has attained genetic diagnosis for the 17 XLID pedigrees. Sanger sequencing and XCI assay can provide auxiliary tests for the diagnosis of XLID.

Objective:To explore the genetic etiology of a pedigree with intellectual disability and explore its pathogenesis.Methods:A Chinese pedigree which had presented at the Henan Provincial People′s Hospital in March 2023 was selected as the study subject. Clinical data of the pedigree were collected, along with peripheral venous blood samples from its members. Whole exome sequencing (WES) was carried out, and candidate variants were verified by Sanger sequencing. Amniotic fluid was collected for prenatal diagnosis. This study was approved by the Medical Ethics Committee of the Henan Provincial People′s Hospital (No. 2019-134).Results:Both the proband (a 6-year-old male) and his mother (30 years old) had various degrees of intellectual and motor impairment. WES revealed that the proband has harbored a de novo heterozygous c. 2563_2567dup (p.Lys856fs) variant of the UBE3A gene, while his mother, maternal grandmother and fetus had all harbored a novel heterozygous c. 409+ 1G>A variant of the RNF13 gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted to be pathogenic (PVS1+ PS1+ PM2_Supporting; PVS1+ PM2_Supporting+ PP3). Conclusion:Based on the clinical manifestations and the result of genetic testing, the heterozygous c.2563_2567dup (p.Lys856fs) variant of the UBE3A gene probably underlay the intellectual disability and developmental delay in the proband, whilst the heterozygous c. 409+ 1G>A variant of the RNF13 gene may underlie the intellectual disability in the proband′s mother and grandmother. Above results have enabled genetic counseling and prenatal diagnosis for this pedigree.

As the most common chromosomal disorder compatible to life, Down syndrome (DS) is caused by an extra copy of chromosome 21. Almost all DS patients have cognitive dysfunction. Therefore, it is important to study the underlying pathogenetic mechanism to elucidate its molecular basis. This article has provided a review for the molecular mechanisms of NRIP1 and DYRK1A genes, which have been closely associated with the cognitive dysfunctions of DS patients. It has also summarized the research progress on the mechanism of DS and development of new therapeutic strategies based on such studies, with an aim to provide insights into the prevention and treatment for the cognitive dysfunctions in DS patients.