OBJECTIVE: To investigate the clinical characteristics and genetic etiology of a fetus with bilateral ear malformation and microphthalmia. METHODS: A fetus diagnosed with Syndromic Microphthalmia 5 (MCOPS5) on January 29, 2024 at Ningbo Women and Children's Hospital was selected as the study subject. A retrospective study was conducted to collect clinical data. Peripheral blood samples (3 mL) were collected from the parents, and amniotic fluid (10 mL) was obtained from the fetus. Genomic DNA was extracted and subjected to whole-exome sequencing (WES). Candidate variants were validated by Sanger sequencing of the family members. The pathogenicity of the candidate variant was classified according to the guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Ethics Committee of Ningbo Women and Children's Hospital (Ethics No.: EC2023-094). RESULTS: The gestational age of the fetus was 23⁺² weeks. Prenatal magnetic resonance imaging (MRI) revealed hypoplastic left external ear, bilateral reduced eyeball volume, and abnormal brain parenchyma development. WES has identified a heterozygous frameshift variant in the OTX2 gene (NM_021728.4: c.706_725del, p.Thr236ProfsTer17). Sanger sequencing confirmed that neither parent has carried the same variant, indicating a de novo origin. According to the ACMG guidelines, this variant was classified as likely pathogenic (PVS1_Strong+PM2_Supporting+PS2_Supporting). CONCLUSION The heterozygous frameshift variant (NM_021728.4: c.706_725del) of the OTX2 gene probably underlay the pathogenesis of this fetus. Above finding has expanded the mutational spectrum of OTX2 gene and may contribute to the understanding of syndromic microphthalmia.
Humans ; Otx Transcription Factors/genetics* ; Female ; Pregnancy ; Phenotype ; Microphthalmos/diagnostic imaging* ; Mutation ; Fetus/abnormalities* ; Male ; Adult ; Retrospective Studies ; Exome Sequencing

OBJECTIVE: To explore the genetic etiology of a Chinese boy affected with Oculo-facio-cardio-dental syndrome (OFCD). METHODS: A child diagnosed with OFCD at West China Hospital of Sichuan University on September 21, 2024 was selected as the study subject. Clinical phenotype of the child was collected through ophthalmologic examination, cardiac ultrasonography, and X-ray imaging. Potential pathogenic variants were detected by trio-whole exome sequencing (Trio-WES). Candidate variant was validated with TA-cloning followed by Sanger sequencing. Mosaic variant was analyzed by ultra-deep sequencing (10,000-fold) and quantitative PCR. This study was approved by the Medical Ethics Committee of the West China Hospital of Sichuan University (Ethics No.: 2019-772 ). RESULTS: The proband had presented with congenital cataracts, mitosis, atrial and ventricular septal defects, dental abnormalities, and right radioulnar synostosis. His mother also exhibited congenital cataracts and dental anomalies, suggesting a diagnosis of OFCD. Trio-WES revealed an novel heterozygous 14-bp deletion (c.4724_4737del) in exon 12 of the BCOR gene in the proband. Deep sequencing identified a mosaic BCOR c.4724_4737del mutation in approximately 3.4% of peripheral leukocytes from his mother. Quantitative PCR analysis also confirmed the presence of this low-level mosaicism. The 14-bp deletion was predicted to cause a frame shift and premature termination (p.Met1575AsnfsTer6). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PVS1+PM2+PP1). CONCLUSION Above findings have expanded the spectrum of BCOR mutations associated with OFCD, which highlighted the role of low-level mosaicism with maternal transmission and provided a basis for genetic counseling and reproductive guidance for the family.
Humans ; Male ; Repressor Proteins/genetics* ; Proto-Oncogene Proteins/genetics* ; Tooth Abnormalities/genetics* ; Eye Abnormalities/genetics* ; Microphthalmos/genetics* ; Child ; Sequence Deletion ; Female ; Cataract/congenital* ; Heart Septal Defects

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with microphthalmia. METHODS: Clinical data of the proband was collected. Whole exome sequencing (WES) was carried out to screen potential pathogenic variants in the proband. Candidate variant was verified by Sanger sequencing of the proband and his family members. Pathogenicity of the variant was predicted by searching the PubMed database and bioinformatic analysis. Sanger sequencing of amniotic fluid sample was carried out for prenatal diagnosis. RESULTS: The proband and his father were found to harbor a heterozygous c.151C>G (p.R51G) variant of the MAB21L2 gene. The same variant was not found in his mother and grandparents. Based on the guidelines of American College of Medical Genetics, the c.151C>G (p.R51G) variant was predicted as likely pathogenic. CONCLUSION The c.151C>G (p.R51G) variant of the MAB21L2 gene probably underlay the microphthalmia in the proband. Above finding has facilitated prenatal diagnosis for this pedigree.
China ; Coloboma ; Eye Proteins ; Female ; Humans ; Intracellular Signaling Peptides and Proteins ; Microphthalmos/genetics* ; Mutation ; Osteochondrodysplasias ; Pedigree ; Pregnancy ; Prenatal Diagnosis

OBJECTIVE: To analyze clinical features and genetic cause for a Chinese pedigree affected with microphthalmia. METHODS: The proband and his parents were subjected to whole exome sequencing (WES) to identify potential pathogenic variants. Sanger sequencing was carried out to confirm the result of WES in available members from the pedigree. Prenatal diagnosis was provided to the proband's mother by genetic testing of amnionic DNA. RESULTS: A heterozygous nonsense mutation c.289C>T (p.R97*) was identified in the OTX2 gene among three patients from the pedigree by WES. The result was confirmed by Sanger sequencing. The proband's mother has carried the same mutation but did not have microphthalmia. The proband's father, aunt and the mother's fetus did not carry the mutation. CONCLUSION The c.289C>T (p.R97*) mutation probably underlies the microphthalmia in this pedigree. Above result has facilitated genetic counseling and prenatal diagnosis.
China ; Female ; Humans ; Male ; Microphthalmos/genetics* ; Mutation ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Whole Exome Sequencing