中华医学遗传学杂志最新文献

Objective: To explore the clinical characteristics and genetic etiology of a child with Osteopathia striata with cranial sclerosis (OSCS) due to variant of AMER1 gene.

Methods: A child presented at the Affiliated Children's Hospital of Zhengzhou University in July 2024 due to growth and development retardation was selected as the study subject. A retrospective study was conducted to collect the child's clinical data. Peripheral blood samples (2 mL each) were collected from the child and her parents, and genomic DNA was extracted for whole exome sequencing (WES). Sanger sequencing was used for the verification of candidate variants. The pathogenicity of variant was rated according to the guidelines from American College of Medical Genetics and Genomics (ACMG). The study has been approved by the Medical Ethics Committee of the Children's Hospital Affiliated to Zhengzhou University (Ethics No.: 2024-108-001).

Results: The patient, a 4-year-and-10-month-old girl, presented with global developmental delay, short stature, cleft palate, distinct facial features, and hearing impairment. WES revealed that she has harbored a heterozygous c.790_794dup (p.Cys265Trpfs*19) variant of the AMER1 gene, which was not detected in either parent. Based on the guidelines from ACMG, the gene variant was classified as pathogenic (PVS1 + PS2 + PM2_supporting). As the result of a non-triplet base insertion in the coding region of the AMER1 gene, it has converted a codon originally encoding an amino acid into a stop codon, and led to a truncated protein, causing severe alteration and dysfunction of the protein.

Conclusion: The child was diagnosed with OSCS for clinical features such as global developmental delay, short stature, cleft palate, distinctive facial features, and hearing impairment, for which the de novo heterozygous frameshift variant AMER1: c.790_794dup (p.Cys265Trpfs*19) may be accountable. Above finding has expanded the mutational spectrum of OSCS and provided a basis for genetic counseling and prenatal diagnosis for the family.

Objective: To assess the association of single nucleotide polymorphisms (SNP) of the cell division cycle 42 (CDC42) gene with Pulmonary artery systolic pressure (PASP) among patients with Congenital heart disease (CHD).

Methods: In this observational study, clinical data and blood samples were collected from 579 CHD patients with left-to-right shunt who presented to our hospital between January 2012 and January 2017. SNPs of the CDC42 gene were genotyped using an improved multiple ligase detection reaction. Multiple linear regression was applied to evaluate the association of CDC42 gene variants with PASP. This study was approved by the Medical Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University (Ethics No.: 20180222-102).

Results: Polymorphisms at rs2501256 and rs34896897 of the CDC42 gene were significantly associated with PASP. Compared with the CC genotype at rs2501256, TT and CT carriers displayed higher PASP [TT vs. CC: B (95%CI) = 4.01 (1.95, 6.07), P < 0.001; CT vs. CC: B (95%CI) = 2.91 (0.63, 5.19), P < 0.001]. Similarly, GG and GA genotypes at rs34896897 were associated with higher PASP compared to the AA genotype [GG vs. AA: B (95%CI) = 26.15 (20.45, 31.84), P < 0.001; GA vs. AA: B (95%CI) = 7.19 (4.31, 10.08), P < 0.001]. Genetic model analyses demonstrated significant differences for both rs2501256 and rs34896897 under dominant, additive, and recessive models (P < 0.05). TT carriers at rs2501256 exhibited larger left-and right-atrial diameters, whereas GG carriers at rs34896897 showed greater right-atrial and right-ventricular end-diastolic dimensions. Subgroup analyses revealed no association between rs2501256 and PASP in males, individuals younger than 18 years, Uyghur ethnicity, or those with ventricular septal defects.

Conclusion: CHD patients carrying the minor alleles of rs2501256 and rs34896897 in the CDC42 gene present higher incidence of PASP compared to those carrying the common alleles.

Objective: The haplotypes of Killer cell immunoglobulin-like receptors (KIR) can be divided into centromeric and telomeric ones. As the terminal gene at the centromeric end, KIR3DP1 plays an important role in stabilizing the haplotype structure. This study aimed to analyze the distribution of KIR3DP1 gene haplotypes among Han Chinese population in Zhejiang in order provide a basis for further analyzing the role of KIR3DP1 in the KIR haplotypes.

Methods: A total of 166 unrelated blood donors from Zhejiang were collected (Blood donation period: March 2020 to August 2020), and genotyping was performed by next-generation sequencing based on exon capture. The copy number and allelic frequency of the KIR3DP1 gene and the distribution of centromeric haplotypes were statistically analyzed. This study was approved by the Medical Ethics Committee of Zhejiang Blood Center (Ethics No.: 2023-001).

Results: The KIR3DP1 gene was positive for all individuals but with different copy numbers. Among these, 4 cases (2.4%) had only 1 copy, 156 cases (94.0%) had 2 copies, and 6 cases (3.6%) had 3 copies. A total of 10 KIR3DP1 alleles were found in the population, which could be classified into the KIR3DP1*001-L type, KIR3DP1*003-L type, and KIR3DP1 full deletion type. The KIR3DP1*003 L type allele was linked to the Cen-A01 and Cen-B01 types, and the KIR3DP1*001*L type allele and the KIR3DP1 deletion type were only present in the Cen-B02 type haplotype.

Conclusion: This study has derived a high-resolution distribution map of the KIR3DP1 gene in the Han population from Zhejiang, and found that the KIR3DP1 alleles showed different linkage with the centromeric haplotypes, which has provided a basis for further studying the role of KIR3DP1 in genetic immunity.

Objective: To explore the clinical phenotype and genetic characteristics of a patient with Progressive pseudorheumatoid dysplasia (PPRD) due to compound heterozygous variants of CCN6 gene.

Methods: A patient who was admitted to Qilu Hospital of Shandong University due to "bilateral finger joint deformity, bilateral hip and knee joint movement limitation for 19 years" was selected as the study subject. Clinical data of the patient were retrospectively collected. Peripheral blood samples were collected from the patient and her parents and subjected to whole exome sequencing (WES). Long-read sequencing (LRS) and Sanger sequencing were used to verify the candidate variants. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of candidate variants was classified. This study was approved by the Medical Ethics Committee of Qilu Hospital of Shandong University (Ethics No.: KYLL-202502 061).

Results: The patient, a 23-year-old female, presented with progressive polyarticular deformity, limited movement and abnormal growth and development since childhood. She was initially misdiagnosed as Ankylosing spondylitis and had poor response to sulphasalazine and etoricoxib treatment. WES revealed that she has harbored two heterozygous variants of the CCN6 gene (NM_198239.2), namely c.348C>A and c.676G>C. LRS confirmed that the two variants are located on two homologous chromosomes and constitute compound heterozygous variants. Based on the ACMG guidelines, both variants were rated as pathogenic (PVS1+PM2_Supporting+PM3; PM1+PM2_Supporting+PM3_Supporting+PM5+PP3_Strong). The c.676G>C variant has not been recorded by the HGMD and ClinVar databases.

Conclusion: The c.348C>A and c.676G>C compound heterozygous variants of the CCN6 gene probably underlay the pathogenesis of PPRD in this patient. Above finding has enriched the mutational spectrum of PPRD and provided a basis for the clinical diagnosis and genetic counseling.

Objective: To analyze the clinical characteristics and genotypic changes of six children with RARS2 gene variants.

Methods: The clinical data of 6 children with RARS2 gene variants diagnosed at the Third Affiliated Hospital of Zhengzhou University from January 2017 to August 2024 were collected. Genetic variants were detected using trio-whole exome sequencing. Genomic DNA was extracted from samples and subjected to high-throughput sequencing. Variants were detected and analyzed using relevant databases and software. Pathogenic variants were validated by Sanger sequencing. The protein structure encoded by a previously unreported variant was predicted using a SWISS-MODEL online server. This study was approved by the Medical Ethics Committee of the Third Affiliated Hospital of Zhengzhou University (Ethics No.: 2024-373-01).

Results: Among the six children, four were males and two were females, with the most recent follow-up age ranging from 1-year-and-1-month to 7 years old. The age of onset was under 1 year in all cases. All six children exhibited seizures, including infantile spasms in three, spasms and tonic spasms in one, and focal seizures in two. One child became seizure-free for 4 ~ 5 years following Valproic acid combined with topiramate and adrenocorticotropic hormone (ACTH) pulse therapy, but subsequently experienced a relapse. Another child has remained seizure-free for nearly one year with oral sodium valproate, levetiracetam, and a "cocktail" therapy. Seizures were not controlled in the remaining four children. Pontocerebellar hypoplasia was observed on neuroimaging in two children. All six patients exhibited severe psychomotor retardation. A total of 10 RARS2 gene variants were identified, three of which were previously unreported.

Conclusion: The predominant clinical features of Pontocerebellar hypoplasia associated with RARS2 gene variants include infantile onset, severe psychomotor retardation or regression, drug-resistant epilepsy, and feeding difficulties. The characteristic neuroimaging finding is pontocerebellar hypoplasia. However, its appearance may vary widely with time. The majority of affected children have a poor prognosis.

Objective: To explore the clinical phenotype and genetic characteristics of a child with hereditary Spastic paraplegia type 52 (SPG52) due to variant of AP4S1 gene.

Methods: A child diagnosed with SPG52 at the Department of Pediatrics of the First Affiliated Hospital of Anhui Medical University in May 2010 was selected as the study subject. Whole-exome sequencing (WES) was carried out for the child and his parents. Candidate variants were confirmed by Sanger sequencing. Pathogenicity of the candidate variant was interpreted according to the guidelines from the American College of Medical Genetics and Genomics (ACMG). The study protocol was approved by the Ethics Committee of the Hospital (Ethics No.: PJ2024-04-56).

Results: The child had presented with global developmental delay from infancy, and featured progressive lower limb spasticity, contractures, talipes equinovarus, and muscle weakness, but with no significant facial dysmorphism. His first febrile seizure occurred before one year of age, followed by several afebrile seizures. The seizures had remitted after 3 to 4 years of antiepileptic therapy, and electroencephalography was normal. However, he had severe intellectual disability, and MRI revealed reduced white matter. WES identified a homozygous AP4S1 c.289C>T (p.Arg97*) variant in the child, for which both of his parents were heterozygous carriers. The variant was rated as pathogenic based on the ACMG guidelines. Literature review has identified 8 publications on SPG52, involving 18 patients from 12 pedigrees. Combined with our case, 14 had carried homozygous variants of the AP4S1 gene, 3 had compound heterozygous variants, and 2 had heterozygous variants, involving 12 distinct variant sites. The cohort included 7 males and 12 females. All patients exhibited progressive lower limb spasticity and weakness as the primary feature, with certain loss of independent ambulation. Most patients had intellectual disability, some had distinctive facial features, though febrile seizures or epilepsy were common. Electroencephalography often showed increased slow-wave activity. Brain MRI frequently demonstrated ventriculomegaly, a thin corpus callosum, and reduced white matter.

Conclusion: The homozygous c.289C>T (p.Arg97*) variant of the AP4S1 gene probably underlay the pathogenesis of SPG52 in this child. Above discovery has expanded the mutational spectrum of AP4S1 and provided valuable insights for the genetic diagnosis, counseling, and clinical management of SPG52.

Objective: To explore the detection rate of copy number variations (CNVs) in fetuses with isolated Congenital anomalies of the kidney and urinary tract (CAKUT) and pregnancy outcomes in order to provide a basis for genetic counseling.

Methods: One hundred and eighty eight fetuses who underwent chromosomal microarray analysis (CMA) due to isolated CAKUT detected by prenatal ultrasonography at Qingdao Women and Children's Hospital from January 2021 to December 2024 were selected as the study subjects. According to the ultrasound findings, the fetuses were divided into 8 groups, including renal parenchymal dysplasia group, renal cystic dysplasia group, simple renal parenchymal echo enhancement group, abnormal development of renal collecting system group, duplicated kidney group, ectopic kidney group, horseshoe kidney group, and bladder/posterior urethral abnormalities group. The detection of CNVs was retrospectively analyzed, and the pregnant women were followed up to summarize their pregnancy outcomes. 2 test (or Fisher's exact probability method) was used to compare the CNV detection rates between the groups. This study was approved by the Medical Ethics Committee of the Qingdao Women and Children's Hospital (Ethics No.: QFELL-YJ-2025-85).

Results: Among the 188 fetuses with isolated CAKUT, 23 CNVs (12.23%) were detected, of which 13 cases (6.91%) were pathogenic and 10 cases were rated as variants of unknown significance (VOUS). Among the 8 groups, the three groups with the highest proportion were renal cystic dysplasia group, renal metaplasia group, and renal parenchymal dysplasia group. The detection rates of pathogenic CNVs in the three groups were 1.79% (1/56), 6.78% (4/59), and 16.67% (5/30), respectively, with statistically significant differences (P < 0.05). Parental verification was conducted on 12 fetuses detected with the CNVs, confirming that 2 cases were de novo and 10 were inherited from parents with a normal phenotype. After genetic counseling, the parents of 9 fetuses opted to terminate the pregnancy, while 11 chose to continue with the pregnancy, and 3 were lost to follow-up. At the time of last follow-up, the youngest offspring was 5 months old and the oldest was 3 years and 11 months old. One child had renal aplasia, and two were born with hydronephrosis, which have been cured through surgery. The remainders had no obvious abnormality with their growth and development.

Conclusion: CMA testing has important value for prenatal diagnosis of isolated CAKUT. In this study, the detection rate of pathogenic CNVs has increased sequentially in fetuses with renal cystic developmental abnormalities, renal collecting system developmental abnormalities, and renal parenchymal dysplasia, while there was no significant difference in the detection rate of CNVs. For fetuses with isolated CAKUT detected by prenatal ultrasound, CMA testing should be considered,

Objective: To explore the clinical manifestation and genotype of a child with Progressive familial intrahepatic cholestasis 8 (PFIC8) due to variant of KIF12 gene.

Methods: A child diangosed with PFIC8 at Changzhou Children's Hospital in October 2017 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples (3 mL each) were collected from the patient, her parents and younger sister. Following extraction of genomic DNA, whole exome sequencing (WES) was carried out. Candidate variants were validated using Sanger sequencing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of candidate variants was classified. This study has been approved by the Medical Ethics Committee of Changzhou Children's Hospital (Ethics No.: 2023-002).

Results: The main clinical manifestations of the child included high GGT cholestasis, portal hypertension, splenomegaly, and abnormal liver enzymes. WES revealed that she has harbored compound heterozygous variants of the KIF12 gene, namely c.245G >A (p.Arg82Gln) and c.1291del (p.Ser431Valfs*13). Bioinformatics analyses showed that both variants were pathogenic. A total of 25 cases were reported in 7 English literature, including 13 males and 12 females. All patients had presented with high GGT cholestasis. Some had progressed to cirrhosis, and 3 cases also had renal lesions. No death was reported. Six children were treated with LTx. Nineteen children were found to harbor homozygous variants of the KIF12 gene, and the remaining six harbored compound heterozygous variants of the same gene. The most common mutation was c.655C>T (p.Arg219*). The mutation sites are mainly located in the Kinesin motor catalytic domain, with high GGT cholestasis as the main clinical feature. No correlation was found between the genotype and phenotype.

Conclusion: PFIC8 caused by KIF12 deficiency is mainly characterized by high GGT cholestasis, for which there is no effective treatment. The c.245G>A and c.1291del compound heterozygous variants of the KIF12 gene probably underlay the pathogenesis in this child.

Objective: To determine the prevalence of GJB2 gene c.109G>A (p.V37I) variant among infants with congenital hearing loss and analyze the initial audiological characteristics of children harboring the variant, compare the audiometric difference among individuals with various genotypes, and explore genetic and audiological manifestations of the affected families.

Methods: One hundred twenty six infants diagnosed with congenital hearing loss at the Neonate Screening Center of Ningbo City from June 2021 to December 2024 were selected as the study subjects. The neonates, in addition with members from 16 of their families, had undergone genetic screening for variants of 208 hotspot sites within 24 deafness-associated genes. For cases identified with monoallelic variants and concurrent hearing loss, the full GJB2 gene was sequenced. Meanwhile, a retrospective analysis was carried out on 23 children whom were confirmed to have hearing loss and the c.109G>A variant by whole exome sequencing from March 2022 to December 2024. And 102 children who were excluded to have hearing loss and pathogenic variants by whole exome sequencing were selected as normal controls. Audiological features of individuals harboring the c.109G>A variant were compared. This study has been approved by the Medical Ethics Committee of The Affiliated Women and Children's Hospital of Ningbo University (Ethics No.: EC2023-009).

Results: For the 126 infants with congenital hearing loss, prospective screening has identified 58 (46.03%) to harbor the c.109G>A variant. These included 38 homozygotes and 16 compound heterozygotes. Retrospective review of the 23 c.109G>A positive children has identified 15 as homozygotes and 8 as compound heterozygotes. Genetic testing of the 16 pedigrees has identified 7 homozygotes and 1 compound heterozygote. For the homozygotes combined (n = 53), 96.2% exhibited bilateral symmetric hearing loss, with 78.3% showing high-frequency sloping patterns, and 98.1% having a hearing threshold ranging from 20 to 65 dB. For the compound heterozygotes combined (n = 24), 95.8% showed symmetric loss, with 59.4% having high-frequency sloping, and 97.9% had a hearing threshold ranging from 20 to 65 dB. Both groups showed significantly elevated ABR/PTA thresholds compared with the normal controls (P = 0.000). The compound heterozygous group had higher ABR thresholds (43.3 ± 15.0 dB nHL) compared with the homozygous group (39.1 ± 12.0 dB nHL, P = 0.005).

Conclusion: Infants harboring the GJB2 c.109G>A variant primarily manifest as mild-to-moderate, symmetric, high-frequency sloping hearing loss. Nearly one-third of affected children have thresholds between 20 to 35 dB nHL, suggesting that ABR > 35 dB nHL alone may underestimate the hearing impairment in this population. Compared with homozygotes, compound heterozygotes with the the GJB2 c.109G>A variant can confer a more severe hearing lo

Objective: To analyze the carrier rates and profiles of pathogenic and likely pathogenic variants for hearing loss-related genes MYO7A, PCDH15, and CDH23 among neonates in Nanjing city through targeted next-generation sequencing (NGS).

Methods: Heel-prick blood samples were collected from 30 043 newborns delivered at Nanjing Women and Children's Health Care Hospital between March 2022 and April 2024. Dried blood spots were prepared, and genomic DNA was extracted. Targeted NGS was applied to detect variants across the full coding regions of the MYO7A, PCDH15, and CDH23 genes. The carrier rates and profiles of pathogenic and likely pathogenic variants of the three genes were analyzed. This study was approved by the Medical Ethics Committee of Nanjing Maternal and Child Health Care Hospital (Ethics No.: 2021KY-071).

Results: The carrier rates of pathogenic and likely pathogenic variants (with ≥ 1 variant site) for the MYO7A, PCDH15, and CDH23 genes were 0.340%, 0.226%, and 0.156%, respectively. A total of 65, 49, and 30 variant types were detected in the MYO7A, PCDH15, and CDH23 genes, respectively. For MYO7A, single base variants were predominant, with the most common variant being c.5581C>T, followed by c.1343+1G>A, c.2837T>G, and c.5660C>T, with allelic frequencies of 0.013% (8/60 086), 0.007% (4/60 086), 0.007% (4/60 086), and 0.007% (4/60 086), respectively. PCDH15 variants were mainly deletions, with the most common variant site being c.4699_4715dupAGAGAAAAGATTCAGAG, followed by c.3441delA, c.440T>G, and c.4733_4736delTCAG, with allelic frequencies of 0.015% (9/60 086), 0.005% (3/60 086), 0.005% (3/60 086), and 0.005% (3/60 086), respectively. For CDH23, single base variants were predominant, with c.6604G>A being the most common, followed by c.6085C>T, c.6050+9G>A, and c.6253+1G>A, with allelic frequencies of 0.013% (8/60 086), 0.012% (7/60 086), 0.005% (3/60 086), and 0.005% (3/60 086).

Conclusion: This study analyzed the carrier rates and profiles of pathogenic and likely pathogenic variants of the MYO7A, PCDH15, and CDH23 genes, which can provide more evidence for the prevention and management of deafness in the region.