To investigate the roles of lactotransferrin gene (LTF, also referred to as the lactoferrin gene, LF), located at 3p21.3 within the common minimal deletion region, in the pathogenesis of nasopharyngeal carcinoma (NPC), we first detected its expression level in 33 primary NPC tissues and 15 chronic nasopharyngitis tissues. Absent expression or downregulation of LTF were observed in 76% (25 of 33) of primary NPC tissues. We further found that 25% (5 of 20) of NPC specimens had loss of heterozygosity (LOH) at the LTF locus. LTF mutation assessed by polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing was noted in 30% (6 of 20) of primary NPC tissues. In addition, hypermethylation of LTF promoter region was found in 63.6% (21 of 33) of primary NPC samples but not in chronic nasopharyngitis tissues. The LTF transcripts in NPC cell lines increased upon treatment with the demethylation compound, 5-aza-2-deoxycytidine. In conclusion, our data indicate that two-hit silencing of LTF through genetic and epigenetic changes may be a common and important event in the carcinogenesis of NPC.

The DLC-1 gene, located at the human chromosome region 8p22, behaves like a tumor suppressor gene and is frequently deleted in diverse tumors. The deletion of 8p22 is not an uncommon event in nasopharyngeal carcinoma (NPC), therefore we explored the expression levels of the DLC-1 gene in NPCs and NPC cell lines by reverse transcription-polymerase chain reaction. The results showed the mRNA level of DLC-1 was downregulated. To identify the mechanism of DLC-1 downregulation in NPC, we investigated the methylation status of the DLC-1 gene using methylation-specific PCR, and found that 79% (31 of 39) of the NPC tissues and two DLC-1 nonexpressing NPC cell lines, 6-10B and 5-8F, were methylated in the DLC-1 CpG island. Microsatellite PCR was also carried out, and loss of heterozygosity was found at four microsatellite sites (D8S552, D8S1754, D8S1790 and D8S549) covering the whole DLC-1 gene with ratios of 33% (4 of 12 informative cases), 18% (2 of 11), 5% (1 of 18), and 25% (3 of 12), respectively. Taken together, our results suggest that DLC-1 might be an NPC-related tumor suppressor gene affected by aberrant promoter methylation and gene deletion.

Background: Nance–Horan syndrome (NHS) is a rare and often overlooked X‐linked dominant disorder characterized by dense congenital cataracts, dental abnormalities, and mental retardation. The majority of NHS variations include frameshift mutations, nonsense mutations, microdeletions, and insertions.Methods: Copy number variation sequencing was performed to determine the microdeletion. The expression of NHS was detected by RT‐PCR. Four family members were tested for X chromosome inactivation.Results: In this study, all members were examined for systemic examinations and genetic testing of four members and two affected subjects are observed. We identified a heterozygous microdeletion of −0.52 Mb at Xp22.13 in a female proband presenting NHS phenotypically. The microdeletion contains the REPS2 and NHS genes and was inherited from a phenotypically normal mother. Of interest, the expression NHS of proband was reduced and the skewed X chromosome inactivation rate reached more than 85% compared with her mother and the control. It was concluded that the haploinsufficiency of the NHS gene may account for the majority of clinical symptoms in the affected subjects. The variability among female carriers presumably results from nonrandom X chromosome inactivation.Conclusion: Our findings broaden the spectrum of NHS mutations and provide molecular insight into NHS clinical prenatal genetic diagnosis.

Congenital contractural arachnodactyly (CCA) is a rare autosomal dominant connective tissue disorder caused by mutations in the fibrillin-2 (FBN2) gene, characterized by crumpled ears, arachnodactyly, camptodactyly, dolichostenomelia, large-joint contractures and thoracolumbar scoliosis. Variations in the FBN2 gene primarily include missense mutations and splice sites mutations. It is crucial to clarify whether missense mutations in the FBN2 gene affect mRNA splicing. We identified a novel pathogenic missense variant (c.3472G > C, p.Asp1158His) in exon 26 of the FBN2 gene using whole-exome sequencing (WES) and Sanger sequencing. In vitro, both the wild-type and mutant minigenes were successfully inserted into the pcMINI and pcMINI-C vectors to verify the impact of this variant on FBN2 mRNA splicing. We utilized CLUSTALW to perform multiple sequence alignment to compare the evolutionary conservation of this variant and employed AlphaFold2 to predict the protein structure of the mutant. The likely pathogenic missense mutation (c.3472G > C) results in the amino acid at position 1158 of the FBN2 changing from aspartic acid (Asp) to histidine (His). Furthermore, DNA multiple sequence alignment indicates that this site is highly evolutionarily conserved. Functional assays and structure prediction indicated that the missense variant located at the edge of exon 26 of FBN2 does not affect RNA splicing, instead, it changes the structure and function of the protein by altering the amino acid sequence. This study enriches the pathogenic spectrum of CCA. Our research provides new insights for the diagnosis of CCA and may have an impact on genetic counseling.

Background: The incidence of spontaneous abortion (SA), which affects approximately 15–20% of pregnancies, is the most common complication of early pregnancy. Pathogenic copy number variations (CNVs) are recognized as potential genetic causes of SA. However, CNVs of variants of uncertain significance (VOUS) have been identified in products of conceptions (POCs), and their correlation with SA remains uncertain. Results: Of 189 spontaneous abortion cases, trisomy 16 was the most common numerical chromosome abnormality, followed by monosomy X. CNVs most often occurred on chromosomes 4 and 8. Gene Ontology and signaling pathway analysis revealed significant enrichment of genes related to nervous system development, transmembrane transport, cell adhesion, and structural components of chromatin. Furthermore, genes within the VOUS CNVs were screened by integrating human placental expression profiles, PhyloP scores, and Residual Variance Intolerance Score (RVIS) percentiles to identify potential candidate genes associated with spontaneous abortion. Fourteen potential candidate genes (LZTR1, TSHZ1, AMIGO2, H1-4, H2BC4, H2AC7, H3C8, H4C3, H3C6, PHKG2, PRR14, RNF40, SRCAP, ZNF629) were identified. Variations in LZTR1, TSHZ1, and H4C3 may contribute to embryonic lethality. Conclusions: CNV sequencing (CNV-seq) analysis is an effective technique for detecting chromosomal abnormalities in POCs and identifying potential candidate genes for SA.