OBJECTIVE: To explore the application value of artificial intelligence (AI)-assisted chromosomal karyotype analysis in the diagnosis of prenatal chromosomal mosaicism. METHODS: A retrospective analysis was conducted on 172 pregnant women who underwent amniocentesis at the Department of Medical Genetics and Prenatal Diagnosis, the Third Affiliated Hospital of Zhengzhou University between January 2019 and December 2024. All cases whose fetuses were diagnosed with chromosomal mosaicism via karyotype analysis and stratified into two groups based on the analytical software employed: the conventional analysis group (n = 70), which utilized Leica analysis software for karyotype image recognition and cell counting; and the AI-assisted analysis group (n = 102), which utilized AI-assisted software for the same procedures. The clinical performance of AI-assisted karyotype analysis in diagnosing chromosomal mosaicism was comprehensively evaluated by comparing the types of mosaic karyotypes, distribution of mosaic ratios, and verification outcomes of different detection modalities between the two groups. This study was approved by the Medical Ethics Committee of the Third Affiliated Hospital of Zhengzhou University (Ethics No.: 2024-406-01). RESULTS: No statistically significant difference was observed in baseline characteristics (maternal age, gestational week, and indications for prenatal diagnosis) between the two groups. Regarding the detection efficacy for numerical and structural mosaicisms, no significant difference was found in the detection of numerical mosaicism. However, the conventional analysis group exhibited a significantly higher detection rate of autosomal structural mosaicism compared to the AI-assisted group (11.43% vs. 0.98%, P < 0.05). Numerical mosaicism cases were further verified using copy number variation sequencing (CNV-seq) and/or fluorescence in situ hybridization (FISH). The AI-assisted group demonstrated a significantly lower inconsistency rate (5.56% vs. 20.41%, P < 0.05) compared to the conventional group. For low-proportion (< 10%) chromosomal mosaicism, the AI-assisted group had a significantly lower detection rate (13.25% vs. 29.69%, P < 0.05). Subsequent validation of low-proportion mosaicism by CNV-seq and/or FISH showed a higher consistency rate in the AI-assisted group (81.82% vs. 54.55%), though the difference did not reach statistical significance (P = 0.360). CONCLUSION For the karyotyping analysis of prenatal chromosomal mosaicism, AI-assisted karyotype analysis shows high accuracy and consistency in identifying numerical chromosomal mosaicism, particularly in reducing the detection of low-proportion (< 10%) mosaicism while improving verification accuracy. AI-assisted analysis can significantly improve the detection accuracy of numerical mosaicism and mitigate the risk of misclassification for low-proportion (< 10%) mosaicism, thereby providing more precise clinical evidence for the prenatal diagnosis of chromosomal mosaicisms.
Humans ; Female ; Mosaicism ; Pregnancy ; Karyotyping/methods* ; Artificial Intelligence ; Prenatal Diagnosis/methods* ; Adult ; Retrospective Studies ; Chromosome Disorders/genetics* ; Amniocentesis

OBJECTIVE: To explore the genetic characteristics of a Chinese pedigree with rare mosaic 11q partial duplication and its pathogenetic mechanisms. METHODS: A pedigree which underwent prenatal diagnosis at Wenzhou Central Hospital between September 25, 2015 and November 30, 2023 was selected for the study. Clinical data were collected from the pedigree. Peripheral blood samples from the parents, amniotic fluid from the fetus, and peripheral blood sample from the neonate were obtained. Genetic testing was carried out by using G-banded chromosomal karyotyping and single nucleotide polymorphism array (SNP-array) technology. Relevant literature was searched in the CNKI, Wanfang Data Knowledge Service Platform, and PubMed databases to summarize the clinical phenotypes of patients with 11q partial duplication. This study was approved by the Medical Ethics Committee of Wenzhou Central Hospital (Ethics No. L2024-07-080). RESULTS: The pregnant woman (G₃) had a history of adverse pregnancy outcomes. During her first pregnancy (G₁), prenatal ultrasound indicated intrauterine growth restriction and a Dandy-Walker variant. Follow-up at 8 years of age showed developmental delays and mild intellectual disability. During her second pregnancy (G₂), prenatal ultrasound revealed nasal bone hypoplasia, and the pregnancy was terminated at 23rd gestational week. During her third pregnancy (G₃), all prenatal tests were normal, and the neonate showed normal growth and development at 4 months of age. The karyotype of amniotic fluid of her first pregnancy was 46,X?, and the SNP-array analysis of neonatal peripheral blood showed arr[GRCh37/hg19]11q13.4q25(70432450_134607121)×2~3, with a mosaicism rate being approximately 40%. The karyotype for her second pregnancy was 46,X?,rec(11)dup(11q)inv(11)(p15q13)dmat[6]/46,X?[27], and the SNP-array result was arr[GRCh38]11q13.4q25(71406636_135067522)×2~3, with a mosaicism rate being approximately 75%. The karyotype for her third pregnancy was 46,X?,inv(11)(p15q13)mat, and the SNP-array result was arr(XN)×1,(1~22)×2. The karyotype of the woman was 46,XX,inv(11)(p15q13), and that of her husband was 46,XY. A review of 12 similar cases (including G₁) from the literature revealed that the common clinical phenotypes of 11q partial duplication included intellectual disability (12/12), developmental delay (12/12), ear abnormalities (12/12), microcephaly (10/12), seizures (8/12), hypotonia (8/12), and congenital heart malformations (7/12). CONCLUSION Mosaic partial duplication of 11q may underlie the genetic etiology of this pedigree. The pregnant woman is a carrier of an inversion on chromosome 11, which might have formed the mosaic 11q partial duplication through meiotic errors and mitotic trisomy rescue mechanisms during reproduction.
Adult ; Female ; Humans ; Male ; Pregnancy ; China ; Chromosome Duplication ; Chromosomes, Human, Pair 11/genetics* ; East Asian People/genetics* ; Karyotyping ; Mosaicism ; Pedigree ; Polymorphism, Single Nucleotide ; Prenatal Diagnosis

OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) for the detection of low-level mosaicisms in amniotic fluid samples, and to retrospectively analyze the rare cases of mosaicisms. METHODS: Chromosomal karyotype of the fetus was determined by G-banding analysis of cultured amniotic fluid cells. CMA was used to detect copy number variation of fetal chromosomes, and fluorescence in situ hybridization (FISH) was used to determine the proportion of fetal chromosomal mosaicisms in uncultured amniotic fluid cells. RESULTS: Among 825 prenatal samples, 4 cases of true fetal mosaicisms were detected, which yielded an incidence of 0.48%. Two cases were sex chromosomal mosaicisms, and two were autosomal mosaicisms, which involved chromosomes 8 and 9, respectively. All cases were verified by G-banding analysis of cultured amniotic fluid cells, CMA, and/or FISH. CONCLUSION CMA has a great value for detecting low-level mosaicisms in amniotic fluid samples, though the positive results need to be verified by other techniques and should be interpreted with caution. The review of rare cases can provide a basis for prenatal genetic counseling.
Humans ; Female ; Amniotic Fluid/metabolism* ; Pregnancy ; Mosaicism/embryology* ; Prenatal Diagnosis/methods* ; Adult ; In Situ Hybridization, Fluorescence ; Microarray Analysis/methods* ; Karyotyping ; Retrospective Studies ; Male

OBJECTIVE: To explore the genetic etiology of two fetuses with Mosaic variegated aneuploidy syndrome (MVA) in a pedigree. METHODS: A 30-year-old pregnant woman, who presented at the Center for Medical Genetics and Prenatal Diagnosis of Shandong Maternal and Child Health Care Hospital on November 16, 2023, was enrolled. Clinical data of the pedigree were collected, and peripheral blood samples from the parents and amniotic fluid samples from the two fetuses were obtained for genomic DNA extraction. Whole exome sequencing (WES) was performed on both fetuses, followed by Sanger sequencing for familial validation and pathogenicity analysis of candidate variants. Chromosomal karyotyping of the parents was conducted to quantify the proportion of premature chromatid separation (PCS). This study was approved by the Medical Ethics Committee of Shandong Maternal and Child Health Care Hospital (Ethics No. 2024-034). RESULTS: Both fetuses exhibited structural brain anomalies and developmental delays during the second trimester. Amniocyte karyotyping revealed low-level mosaic aneuploidy involving multiple chromosomes, while chromosomal microarray analysis (CMA) showed no abnormalities. Pregnancy termination was performed for fetus 1. WES identified compound heterozygous variants in BUB1B, i.e., c.2363_2364del (p.S788Cfs*29) and ss804270619: G>A, in both fetuses. Sanger sequencing confirmed paternal inheritance of c.2363_2364del and maternal inheritance of ss804270619:G>A. According to the American College of Medical Genetics and Genomics (ACMG) and Clinical Genome Resource (ClinGen) Standards and Guidelines for the Interpretation of Sequence Variants, the c.2363_2364del variant was classified as likely pathogenic (PVS1 + PM2_Supporting). Parental karyotyping demonstrated PCS traits, with a higher proportion of abnormal metaphases in the father. CONCLUSION The compound heterozygous variants c.2363_2364del (p.S788Cfs*29) and ss804270619: G>A in BUB1B may constitute the genetic etiology of the two MVA fetuses in this pedigree.
Humans ; Female ; Pregnancy ; Adult ; Mosaicism ; Protein Serine-Threonine Kinases/genetics* ; Chromosome Disorders/diagnosis* ; Pedigree ; Heterozygote ; Prenatal Diagnosis ; Aneuploidy ; Male ; Fetus ; Karyotyping

OBJECTIVE: To explore the genetic characteristics and pathogenesis for a child with mosaicism trisomy 21 and Congenital leukemia (CL). METHODS: A child who was admitted to Ningbo Women and Children's Hospital in March 2023 was selected as the study subject. A retrospective analysis was carried out on the clinical data, laboratory test results, immunophenotyping, and genetic characteristics of the child. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: EC2024-063). RESULTS: Whole genome sequencing (WGS) revealed that the child has mosaicism trisomy of chromosome 21, with a ratio of approximately 74%. In addition, copy number variations involving multiple OMIM genes that could explain his clinical phenotype were detected and rated as pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). No pathogenic variant was detected with the GATA1 gene. Blood immune typing of the child conformed to the immunophenotype of acute myeloid leukemia. CONCLUSION For children with trisomy 21, even in the absence of GATA1 gene variants, the occurrence of CL should be monitored, and early diagnosis and treatment are of great significance for improving the prognosis.
Child, Preschool ; Humans ; DNA Copy Number Variations/genetics* ; Down Syndrome/genetics* ; GATA1 Transcription Factor/genetics* ; Leukemia/congenital* ; Mosaicism ; Mutation ; Retrospective Studies ; Whole Genome Sequencing

OBJECTIVE: To explore the mechanism for the occurrence and phenotypic characteristics of Turner syndrome based on a prenatally diagnosed case of a mosaic karyotype containing double pseudo-isodicentric X chromosome and a review of relevant literature. METHODS: A fetus diagnosed with increased risk for trisomy 21 at the Provincial Hospital Affiliated to Shandong First Medical University in August 2023 was selected as the study subject. Clinical data of the fetus was collected. Following amniocentesis, chromosomal G-banding karyotype analysis and chromosomal microarray analysis (CMA) were carried out. This study has been approved by the Ethics Committee of the Hospital (Ethics No.: SWYX No. 2022-287). RESULTS: The early-trimester screening suggested a high risk of trisomy 21 (1/19), with free β-hCG of 116 ng/mL (MoM value 2.35), PAPP-A of 0.394 ng/mL (MoM value 0.12), and NT value of 1.3 mm, though no abnormality was found in the fetus at 19 weeks gestation. The karyotype of amniocyte was determined as 46,X,psu idic(X)(p11.21)[55]/45,X[27]/47,X,psu idic(X)(p11.21)×2[5]/46,XX[13]. CMA has yielded a result of arr[GRCh37] Xp22.33p11.21(168552_55585678)×1[0.67],Xp11.21q28(55703291_155233098)×3[0.5]. CONCLUSION Karyotypes of Turner syndrome are complex and diverse, and a rare 46,X,psu idic(X)(p11.21)[55]/45,X[27]/47,X,psu idic(X)(p11.21)×2[5]/46,XX[13] mosaic karyotype with double pseudo-isodicentric X chromosome has been identified. Literature review suggested that this karyotype may lead to phenotypic diversification and a risk of reduced sensitivity to hormone therapy.
Humans ; Turner Syndrome/diagnosis* ; Female ; Pregnancy ; Chromosomes, Human, X/genetics* ; Mosaicism ; Prenatal Diagnosis ; Karyotyping ; Adult ; Karyotype ; Amniocentesis

OBJECTIVE: To report on a case of mosaicism involving trisomy 21, maternal uniparental isodisomy, and normal diploid cells in uncultured amniocytes, and to explore the discrepancies between conventional cytogenetic and molecular cytogenetic techniques during prenatal diagnosis. METHODS: A 30-year-old pregnant woman who presented to Boai Hospital of Zhongshan on June 27, 2023 has undergone amniocentesis at 16 weeks of gestation. The amniotic fluid sample was subjected to quantitative fluorescent PCR (QF-PCR), G-banded karyotype analysis, and chromosomal microarray analysis (CMA). The discrepancies between the results of each method were analyzed. This study was approved by Medical Ethics Committee of Boai Hospital of Zhongshan (Ethics No.: KY-2024-001-01). RESULTS: Non-invasive prenatal testing (NIPT) at 12 weeks indicated a high risk of trisomy 21. QF-PCR of uncultured amniocytes revealed a pattern of trisomy 21. After one week of cell culture, G-banding analysis showed mos 47,XX,+21[1]/46,XX[72]. CMA revealed a homozygous state of chromosome 21 in cultured cells, while uncultured amniocytes showed mosaic trisomy 21 with an estimated proportion of 50%. These findings suggested a complex chromosomal mosaicism in the fetus, which may result from a trisomy rescue event during early embryogenesis, leading to coexistence of three cell lines including trisomy 21, maternal uniparental isodisomy, and normal diploid cells. CONCLUSION In prenatal diagnosis, discrepancies may arise between QF-PCR and conventional chromosomal karyotyping analysis, particularly in complex genetic phenomena such as trisomy rescue and uniparental disomy. For cases where NIPT indicated a high risk of trisomy 21 but G-banding karyotype analysis yielded a normal result, further molecular genetic testing using uncultured cells is recommended.
Humans ; Female ; Mosaicism ; Pregnancy ; Uniparental Disomy/diagnosis* ; Adult ; Down Syndrome/diagnosis* ; Prenatal Diagnosis/methods* ; Diploidy ; Karyotyping ; Amniocentesis

Disorders of sex development (DSD) are characterized by atypical development of chromosomal, gonadal, or phenotypic sex. 45X,46XY mosaicism is a type of sex chromosome DSD which presents with a wide heterogeneity of manifestations. We report the case of a 13-year-old phenotypically female who presented with clitoromegaly at puberty. Testosterone level was elevated on serology. Out of the 50 cells examined, 43 cells had Monosomy X while 7 cells had a normal male karyotype. She was managed by a multidisciplinary team. Due to the presence of Y chromosome, the solid nodular structure seen on the right gonad in magnetic resonance imaging and the pain caused by the phallus, Laparoscopic bilateral gonadectomy, salpingectomy and clitoroplasty were done after a shared decision making. Histopathology revealed Gonadoblastoma and Germ cell neoplasia-in-situ of the right gonad justifying timely removal. She was then maintained on estrogen for induction of secondary sexual characteristics.

Proteus syndrome (PS) is a mosaic disorder characterized by asymmetric overgrowth of a variety of tissues. Diagnostic criteria established in 1999 emphasized the mosaic distribution of lesions, progressive course, and disproportionate overgrowth. We present a case of proteus syndrome in a 12-year-old Filipino male with 9 year-history of enlargement of the left foot with soft, non-tender mass on the sole with a brain-like surface. Skin punch biopsy of the mass showed cerebriform connective tissue nevi which is pathognomonic of PS.

PS is a very rare disease with prevalence of less than 1 in 1,000,000 live births. Management of PS is extremely challenging, owing to the combination of the individuality of each case, the severity of the disease, and the risks of complications from procedures. A multidisciplinary clinical approach is strongly recommended to obtain the best possible management plans for individual patients.

Pregnancy ; Female ; Humans ; Mosaicism ; Prenatal Diagnosis ; Prenatal Care ; Aneuploidy