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.

Objective:To analyze the genetic variant characteristics of primary immunodeficiency diseases (PID) in families from Henan Province.Methods:This study conducted a retrospective analysis of 19 PID pedigrees referred to the Prenatal Diagnosis Center at Henan Provincial People's Hospital between January 2016 and March 2024. Among the 19 families, 13 underwent prenatal diagnosis at our hospital, while the remaining six received genetic counseling based on third-party genetic testing reports (confirmed by our institution's laboratory). The clinical data from these families were analyzed, and descriptive statistical analysis was applied to the data.Results:Among the 19 PID families, there were seven cases of combined immunodeficiency, three immunodeficiency syndromes, three phagocyte deficiencies, three antibody-dominant immunodeficiencies, and three immunodysregulatory disorders, involving a total of 12 genes ( IL2RG, ADA, RAG2, STAT3, SMARCAL1, ATM, POLA1, CYBB, BTK, RAB27A, LRBA, IL10R). A total of 25 genetic variants were identified, including 11 novel variants not previously documented in the ClinVar and HGMD professional databases. The novel variants comprised: IL2RG gene mutations (Exon5_8del and c.903_904delinsCT leading to p.E302*), ADA gene mutation (c.884A>G resulting in p.D295G), RAG2 gene mutation (c.513dupA causing p.W172Mfs3), POLA1 gene mutation (c.25+5G>C), CYBB gene mutations (c.824G>A/p.G275D and c.472A>T/p.K158), BTK gene mutations (c.522_523insC/p.A175fs and c.142-2A>C), and RAB27A gene mutations (c.121delA/p.T41fs and c.272delA/p.D91fs). Among the 13 families undergoing prenatal diagnosis, genetic testing revealed that 11 fetuses carried wild-type genes, and these families elected to continue their pregnancies. One fetus exhibited identical genetic variants to the proband and received a clinical diagnosis consistent with the genetic disorder, while another fetus demonstrated chromosomal copy number variations. In both of these latter cases, the families opted for pregnancy termination. Conclusion:This study identified 11 unreported variants across seven genes, highlighting the need for further expansion of PID genetic variant databases.

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 analyze the genetic variant characteristics of primary immunodeficiency diseases (PID) in families from Henan Province.Methods:This study conducted a retrospective analysis of 19 PID pedigrees referred to the Prenatal Diagnosis Center at Henan Provincial People's Hospital between January 2016 and March 2024. Among the 19 families, 13 underwent prenatal diagnosis at our hospital, while the remaining six received genetic counseling based on third-party genetic testing reports (confirmed by our institution's laboratory). The clinical data from these families were analyzed, and descriptive statistical analysis was applied to the data.Results:Among the 19 PID families, there were seven cases of combined immunodeficiency, three immunodeficiency syndromes, three phagocyte deficiencies, three antibody-dominant immunodeficiencies, and three immunodysregulatory disorders, involving a total of 12 genes ( IL2RG, ADA, RAG2, STAT3, SMARCAL1, ATM, POLA1, CYBB, BTK, RAB27A, LRBA, IL10R). A total of 25 genetic variants were identified, including 11 novel variants not previously documented in the ClinVar and HGMD professional databases. The novel variants comprised: IL2RG gene mutations (Exon5_8del and c.903_904delinsCT leading to p.E302*), ADA gene mutation (c.884A>G resulting in p.D295G), RAG2 gene mutation (c.513dupA causing p.W172Mfs3), POLA1 gene mutation (c.25+5G>C), CYBB gene mutations (c.824G>A/p.G275D and c.472A>T/p.K158), BTK gene mutations (c.522_523insC/p.A175fs and c.142-2A>C), and RAB27A gene mutations (c.121delA/p.T41fs and c.272delA/p.D91fs). Among the 13 families undergoing prenatal diagnosis, genetic testing revealed that 11 fetuses carried wild-type genes, and these families elected to continue their pregnancies. One fetus exhibited identical genetic variants to the proband and received a clinical diagnosis consistent with the genetic disorder, while another fetus demonstrated chromosomal copy number variations. In both of these latter cases, the families opted for pregnancy termination. Conclusion:This study identified 11 unreported variants across seven genes, highlighting the need for further expansion of PID genetic variant databases.

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 phenotype and genetic characteristics of probands in 3 pedigrees of complex hereditary spastic paraplegia type 5 (HSP5) who developed symptoms during childhood, and the genetic diagnostic methods of HSP5 to improve the diagnosis and differential diagnosis of this disease.Methods:The clinical data of 3 HSP5 families admitted to Henan Provincial People′s Hospital from June 2020 to January 2023 were collected. Whole exome sequencing (WES) was performed on the patients to analyze phenotype-related single nucleotide variation (SNV) and small fragment insertion/deletion (INDEL) variation. At the same time, the sequencing data were used to analyze the dynamic mutation regions of specific genes.Results:The probands in the 3 families had complex HSP: the proband in family 1 showed weakness of both lower limbs, urgency of urination and ataxia; the proband in family 2 showed slightly lower intelligence, weakness of both lower limbs, dysarthria, and brain magnetic resonance imaging showed white matter lesions; the proband in family 3 showed muscle weakness, spasm, frequent urination and ataxia of both lower limbs. The sequencing results showed that the CYP7B1 gene c.1171G>T (paternal) and c.1249C>T (maternal) compound heterozygous mutations were found in proband 1 and his younger brother. The CYP7B1 gene c.334C>T (paternal) and c.259+2T>C (maternal) compound heterozygous mutations were found in proband 2 and her younger sister. The CYP7B1 gene c.334C>T (paternal) and c.1082G>A (maternal) compound heterozygous mutations were found in proband 3. And c.1171G>T was a new variant that had not been reported before. Dynamic mutation analysis showed that the numbers of CAG repeats of ATXN1/2/3/6/7/8/12, DRPLA, TBP genes were within the normal range. According to the clinical manifestations and genetic examination results of the children in the 3 pedigrees, the diagnosis of HSP5 was clear. Conclusions:The 3 families in the study all had complex HSP5 caused by compound heterozygous mutations of the CYP7B1 gene. WES can analyze SNV, INDEL and dynamic mutations simultaneously to make the maximum clear diagnosis and can be used as an effective detection method for HSP5.

Objective:To analyze the genetic etiology and prognosis in fetuses with increased nuchal translucency (NT) in order to assist in the clinical prenatal genetic counseling and diagnosis.Methods:This study retrospectively enrolled 1 658 cases of singleton pregnancy (<35 years old) receiving invasive prenatal diagnosis, including karyotype analysis and/or chromosome microarray analysis or copy number variation (CNV) sequencing, due to NT value ≥2.5 mm in the first trimester in Henan Provincial People's Hospital from August 2014 to December 2021. They were divided into different groups according to the thickness of NT (≥2.5-<3.0, ≥3.0-<3.5, ≥3.5-<4.5, ≥4.5-<5.5, ≥5.5-<6.5 and ≥6.5 mm groups) and abnormal ultrasound findings (isolated increased NT group, increased NT complicated by soft markers/non-severe structural abnormality group and increased NT complicated by severe structural abnormality group). The results of invasive prenatal diagnosis and pregnancy outcomes were compared between different groups using Chi-square test and trend Chi-square test. Results:The detection rates of numerical abnormalities of chromosomes were 15.8% (262/1 658) and 17.6% (252/1 431) when the NT thickness cut-off value were 2.5 mm or 3.0 mm, respectively. Overall, the detection rate of numerical abnormalities of chromosomes increased with thickness of NT ( χ2trend=180.75, P<0.001), ranging from 6.6% (44/671) in the NT≥2.5-<3.5 mm group to 45.6% (113/248) in the NT≥5.5 mm group. The incidence of pathogenic/likely pathogenic CNV(P/LP CNV) did not increased with NT thickness ( χ2trend=3.26, P=0.071), and the highest detection rate was observed in the NT≥4.5-<5.5 mm group (9.0%, 19/211). The detection rate of numerical abnormalities of chromosomes plus P/LP CNV in the isolated NT≥2.5-<3.0 mm group and NT≥3.0-<3.5 mm group were 5.3% (10/188) and 9.6% (36/375), respectively, however, the difference was not statistically significant ( χ2=3.06, P=0.080). The detection rates of numerical abnormalities of chromosomes plus P/LP CNV in the isolated NT≥3.5-<4.5 mm group and NT≥2.5-<3.0 mm complicated by soft markers/ non-severe structural abnormality group were 12.7% (52/410) and 24.1% (7/29), respectively, and the risk were 2.6 times (95% CI: 1.3-5.2) and 5.7 times (95% CI: 2.0-16.4) of the isolated NT≥2.5-<3.0 mm group, respectively. The pregnancy termination rate increased with the NT thickness ( χ2trend=304.42, P<0.001), ranging from 10.8% (23/212) in the NT≥2.5-<3.0 mm group to 90.7% (117/129) in the NT≥6.5 mm group. After exclusion of the pregnancies terminated due to numerical abnormalities of chromosomes and P/LP CNV, 87.6% (862/984) of the fetus with increased NT were born alive. Conclusions:The detection rate of numerical abnormalities of chromosomes increases with the thickness of NT. Invasive prenatal diagnosis is required for non-advance aged singleton pregnant women when fetuses present with isolated NT≥2.5 mm with or without soft markers/structural abnormalities.

Dystrophinopathies, including Duchenne muscular dystrophy, Becker muscular dystrophy and dilated cardiomyopathy, are X-linked recessive genetic disorders due to variants of the dystrophin gene, which can seriously affect quality of life and health. Genetic diagnosis plays a crucial role in their diagnosis, treatment, and prevention. How to rationally select and standardize the use of various genetic techniques is a skill that clinicians must acquire. By compiling expertise of experts from the relevant areas and guidelines published home and abroad, this consensus has provided a guidance from the perspective of genetic diagnosis for the selection of genetic techniques, testing strategies, and detection process for dystrophinopathies.
Humans ; Quality of Life ; Consensus ; Dystrophin/genetics* ; Muscular Dystrophy, Duchenne/therapy* ; Cardiomyopathy, Dilated/genetics* ; Electrocardiography