中华医学遗传学杂志最新文献

Objective: To explore the clinical and genetic features of a child with Pontocerebellar hypoplasia type 2B (PCH2B) due to compound heterozygous variants of the TSEN2 gene.

Methods: A PCH2B patient presented at Department of Pediatric Neurology, Xiangya Hospital of Central South University in June 2023 was selected as the study subject. Clinical data of the patient were retrospectively analyzed. The patient and her parents were subjected to whole exome sequencing and bioinformatic analysis. Pathogenicity of the candidate variants were classified based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). A literature review was also conducted by searching the China National Knowledge Infrastructure (CNKI), Wanfang Data, and PubMed databases from their establishment to May 2025 using keywords "TSEN2 gene" "PCH2B" and "Pontocerebellar Hypoplasia 2B" to summarize the clinical and genotypic features of patients with PCH2B due to variants of the TSEN2 gene. This study was approved by the Medical Ethics Committee of the Hospital (No.: #202310892).

Results: The patient, a 6-year-5-month-old girl, had exhibited severe global developmental delay, developmental regression, autism spectrum disorder, myoclonus of eyelids, feeding difficulty, irritability, progressive microcephaly, esotropia, and hypotonia. MRI showed reduced volume of bilateral cerebellar hemispheres and vermis. Genetic testing revealed that she has harbored compound heterozygous variants of the TSEN2 gene (NM_025265.4), namely c.1054A>T (p.Lys352*) and c.899G>T (p.Ser300Ile), which were inherited from her father and mother, respectively. Both variants were classified as likely pathogenic based on the ACMG guidelines and were previously unreported. Literature review has identified six PCH2B patients with missense, nonsense, frameshift, and splice site variants of the TSEN2 gene. Their main clinical manifestations included global developmental delay, progressive microcephaly, feeding difficulties, irritability, and vermis hypoplasia. Cranial MRI and genetic testing are crucial for definite diagnosis.

Conclusion: The c.1054A>T (p.Lys352*) and c.899G>T (p.Ser300Ile) compound heterozygous variants of the TSEN2 gene probably underlay the pathogenesis in this patient. Above findings has expanded the genotypic and phenotypic spectra of TSEN2-related PCH2B, and offered guidance for genetic counseling for this family.

Objective: To explore the prenatal and postnatal phenotypes of 22q11.2 microdeletion syndrome (22q11.2DS) and enhance clinical understanding of this condition.

Methods: Data were collected from 86 fetuses diagnosed with 22q11.2DS at four prenatal diagnostic centers across China between January 2014 and August 2025. Prenatal imaging findings, pregnancy outcomes, and postnatal conditions were analyzed.

Results: Among the 86 fetuses, complete ultrasound data were available for 65 cases. Cardiovascular abnormalities were observed in 42 cases, thymic hypoplasia or aplasia in 7 cases, urinary system anomalies in 6 cases, nuchal translucency (NT) thickening in 7 cases, butterfly vertebrae, clubfoot, omphalocele and diaphragmatic hernia in 1 case each, cleft lip and palate in 2 cases, and ultrasound soft markers in 13 cases. The parents of 9 fetuses opted to continue with the pregnancy. Among these, 6 showed no significant ultrasound abnormalities and no related phenotypes postnatally, while the remaining 3 exhibited ultrasound anomalies with postnatal manifestations including developmental delay, immunodeficiency, and cardiac defects.

Conclusion: Fetuses with 22q11.2DS may exhibit various ultrasound abnormalities in multiple systems before and after birth. In addition to cardiovascular anomalies, they may also present with thymic hypoplasia or aplasia, thickened NT, and urinary abnormalities. Fetuses with thickened NT or thymic anomalies should be closely monitored, and thymic assessment should be included in routine prenatal imaging evaluations. For fetuses with 22q11.2DS who show no ultrasound abnormalities, the risk of developing severe phenotypes after birth is relatively low, but occult palate clefts and psychiatric disorders cannot be ruled out. Due to limitations in sample size and follow-up duration, above conclusions require further validation through large-scale prospective studies.

Primordial dwarfism (PD) refers to a group of monogenic genetic disorders characterized by intrauterine growth restriction (IUGR) and severe, persistent postnatal growth retardation. These diseases have been associated with variants of multiple genes whose products are mainly involved in critical cellular biological processes such as maintenance of genomic stability, DNA damage repair, mRNA splicing regulation, and centrosome function. Variants of such genes can directly impair cell proliferation and developmental potential. With the widespread application of molecular genetic technologies such as high-throughput sequencing, significant progress has been made in the research of PD. This article focuses on the major subtypes of PD, including Seckel syndrome, Microcephalic osteodysplastic primordial dwarfism (MOPD) types I/III, MOPD type II, and Meier-Gorlin syndrome. It has systematically summarized the advances in their clinical phenotypic characteristics, pathogenic genes, and molecular mechanisms, with an aim to deepen the understanding of the essence of growth disorders associated with PD.

Objective: To explore the genetic etiology for a pregnant woman with a history of multiple adverse pregnancies and assess the phenotype-genotype correlation of 22q11.2 microduplication syndrome in her family.

Methods: Amniotic fluid sample was taken from a pregnant woman for whom non-invasive prenatal screening indicated chromosome 22 abnormalities in the fetus. Peripheral blood samples from the woman, her brother and parents were collected for high-throughput low-depth whole genome sequencing (CNV-seq). A pedigree traceability analysis of the results was conducted in conjunction with analysis of clinical manifestation. Relevant literature (from establishment to March 2025) was systematically searched. This study was approved by the Medical Ethics Committee of Mianyang Maternal and Child Health Care Hospital (Ethics No.: Lun Shen [2024]009).

Results: CNV-seq revealed that the fetus had harbored a 6.02 Mb duplication at 22q11.21q11.23. Karyotyping confirmed it as 46,X?dup(22)(q11.2). Pedigree verification demonstrated that the pregnant woman, her brother and mother had all carried the same duplication. Phenotypic analysis of the affected family members showed classic features of 22q11.2 microduplication syndrome, including hypernasal speech, low nasal bridge, congenital heart disease, and cognitive impairment. A total of 44 cases with full information (including three patients from this pedigree) were included in the analysis. The penetrance of 22q11.2 duplication was approximately 29.5% (13/44), and 52.3% (23/44) of the cases had inherited the variant from a phenotypically normal parent.

Conclusion: This study has identified the genetic basis for the woman's recurrent adverse pregnancies and phenotypic abnormalities in her family members. The scoliosis identified in her younger brother has not been previously reported, thereby may enrich the clinical phenotype of this syndrome. For fetuses identified with a 22q11.2 microduplication, detailed fetal imaging is recommended, and genetic counseling should be provided to the couples.

Objective: To develop a user-friendly visualization application for the automatic annotation of Human Phenotype Ontology (HPO) terms based on large language models and retrieval-augmented generation (RAG) technology, and to validate its performance in an authoritative case dataset.

Methods: By integrating the domestic open-source large language model DeepSeek-V3 with RAG technology, an interactive web application was deployed on the Streamlit cloud platform. Using only the latest official HPO dataset as the data source, the lightweight sentence-embedding model BAAI/bge-small-en-v1.5 was employed to construct a FAISS vector index. During the online phase, a four-step closed-loop process is automatically completed: multilingual translation, phenotype phrase extraction, RAG candidate retrieval, term mapping, and official database validation. 121 English case reports publicly released by BMJ Case Reports and Oxford Medical Case Reports (with a gold-standard HPO set of 1 794 terms) were selected for application validation. Precision, recall, and F1 score were calculated and compared horizontally with traditional dictionary tools, standalone large language models, and the similar application "RAG-HPO". Finally, replace the model with the more advanced ChatGPT-5 and evaluate its performance on the newly extracted dataset.

Results: An HPO term automatic annotation visualization application named PhenoRAG, based on large language models and RAG technology, was successfully developed. Users can access it directly via a web link. Across the 112 cases, a total of 2 150 HPO terms were generated; 2,064 (96.0%) were fully validated by the official database, with a hallucination rate of 1.3% and an HPO ID-name mismatch rate of 2.7%. After deduplication, 1,906 terms remained for testing. The overall precision was 63.65%, recall was 67.34%, and F1 was 65.44%, significantly outperforming traditional annotation tools (F1: 0.45-0.49, P < 0.001). Although PhenoRAG's F1 was lower than that of RAG-HPO (F1 = 0.78, P < 0.001), which relies on a manually constructed synonym database of 54 000 entries plus the HPO dataset, it requires no additional dictionary maintenance and can be used without any background in computer programming. Moreover, after switching to the GPT-5 model, PhenoRAG exhibited no hallucination rate on the new dataset, and its F1 score significantly increased (P = 0.038).

Conclusion: Without constructing a synonym database, the PhenoRAG achieved high-accuracy automatic mapping from clinical text to standard HPO terms. It features a low usage threshold, free access, and a Chinese-language interface, and can directly serve rare disease diagnosis, genetic counseling, and research scenarios in China and worldwide, warranting further clinical promotion and multicenter validation.

The doublecortin (DCX) gene encodes DCX, a microtubule-associated protein that plays a crucial role in brain development. DCX variants can disrupt microtubule binding and stabilization, interfere with intracellular transport, and affect post-translational modifications. A correlation exists between variant types and clinical severity. Animal models and induced pluripotent stem cell (iPSC) models simulating DCX deficiency revealed the dynamic progression of the disease, which has provided a powerful tool for investigating disease mechanisms and screening therapeutic agents. Currently there is no cure for DCX variants, with treatment primarily relying on anti-epileptic drugs and symptom management. Basic research is now offering new avenues for future therapeutic approaches. This article has summarized the potential pathogenic mechanisms and therapeutic strategies for the DCX variants, with an aim to provide insights for clinical treatment.

Objective: To summarize the clinical and genetic characteristics of a child with 46,XX Ovotesticular disorder of sex development (46,XX OTDSD) due to copy number variation of SOX3 gene.

Methods: A 46,XX male patient presented at the Capital Center for Children's Health, Capital Medical University in November 2024 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples were taken from the child and his parents and subjected to trio whole-genome sequencing. Skewed X-chromosome inactivation was tested in the child and his mother. A literature review was carried out on 46,XX males associated with mutations of the SOX3 gene. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: SHERLL2025056).

Results: The 10-year-old boy presented with hypospadias and cryptorchidism at birth. Chromosome analysis at one year and a half revealed a 46,XX karyotype. Gonadal biopsy showed testicular tissue, while ultrasound at the age of 10 detected ovotesticular tissue. Whole-genome sequencing identified a 660 kb duplication in the Xq27.1 region, which was derived from his mother. X-chromosome inactivation testing showed random inactivation in the child and mild non-random inactivation in the mother. Literature review has found 11 publications involving 15 patients (including our case), among whom 14 had a male social gender. They had primarily presented with hypospadias at birth but had no significant endocrine abnormalities. Most patients had experienced testicular failure after puberty. SOX3 related 46,XX males are mainly caused by de novo duplications, although a few maternal carriers had been discovered.

Conclusion: Duplication of the SOX3 gene probably underlay the pathogenesis is this 46,XX male. Individuals with 46,XX SRY negative male phenotypes should be routinely screened for SOX3 gene variants. Structural variations of the SOX3 gene can lead to complete or partial sex reversal in 46,XX individuals with minimal impact on intellectual and motor development, as well as other endocrine hormones.

Objective: Chromosome conformation-based karyotype analysis (C-MoKa) technology was used to test a couple who had experienced multiple adverse pregnancies in order to provide them with genetic counseling and reproductive guidance.

Methods: A couple presented at the Reproductive Medicine Center of the First Hospital of Lanzhou University in 2023 was selected as the study subject. Through C-MoKa testing, copy number variation sequencing (CNV-seq), and preimplantation genetic testing for aneuploidy (PGT-A), it was found that the couple's repeatedly miscarried fetuses and abnormal embryos exhibited highly similar chromosomal structural abnormalities. Using C-MoKa, the potential genetic abnormalities in both partners were traced, and reproductive guidance was provided based on the result. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: LDYYSZLLKH2025-09).

Results: CNV-seq analysis of the couple's miscarriage fetal chorionic villi showed del(18)(q21.2q23)(28.90 Mb) and dup(13)(q31.2q34)(26.26 Mb). Chromosomal karyotyping analysis of both partners showed no abnormality. From 2024 to 2025, the couple underwent three rounds of PGT-A assisted reproduction. The first embryo test showed del(13)(q31.2q34)(26.77 Mb) and dup(18)(q21.2q23)(29.08 Mb). The second embryo test showed dup(13)(q31.2q34)(26.26 Mb) and del(18)(q21.2q23)(28.90 Mb). And the third embryo test results showed complex chromosomal abnormalities. In 2025, after genetic counseling, the couple had opted C-MoKa test, which has detected no abnormality in the wife, but a balanced 46,XY,t(13;18)(q31.2;q21.2) translocation in the husband.

Conclusion: As a high-throughput sequencing method based on the three-dimensional conformation of chromatin, C-MoKa has the advantages of high resolution and high accuracy, and can accurately detect balanced translocations with similar banding patterns. It has therefore offered a powerful new tool for chromosomal analysis.

Achondroplasia (ACH) is a common inherited skeletal dysplasia (inherited dwarfism) that compromises quality of life across the lifespan. In 2021, vosoritide became the first approved precision therapy for ACH and is now available in more than 40 countries. Compared with prior symptomatic measures, vosoritide has demonstrated favorable efficacy and a reassuring safety profile. Nevertheless, existing international ACH guidelines largely emphasize complication management and symptomatic care, and there is no unified consensus on pharmacologic therapy. To address this gap, an international expert group developed the International Consensus Guidelines for the Implementation and Monitoring of Vosoritide Therapy in Patients with Achondroplasia providing systematic recommendations that span the continuum of care - from initial patient contact and pre-treatment assessment to medication counseling, injection training, and long-term outcome monitoring. These recommendations complement and refine current management and nursing protocols for individuals with ACH and offer practical guidance for clinicians across diverse regions. This article highlights key elements of the guideline to provide evidence-based support and clinical direction for healthcare professionals in China treating children with ACH using vosoritide.