Analysis of two pedigrees with congenital hypodysfibrinogenemia caused by two compound heterozygous variations
10.13602/j.cnki.jcls.2025.02.03
- VernacularTitle:2个复合杂合变异致遗传性低且异常纤维蛋白原血症家系分析
- Author:
Qiyu XU
1
;
Xiaoyong ZHENG
1
;
Fei XU
1
;
Longying YE
1
;
Ke ZHANG
1
;
Mingshan WANG
1
;
Lihong YANG
1
Author Information
1. 温州医科大学附属第一医院医学检验中心,浙江省检验诊断及转化研究重点实验室,浙江温州 325015
- Publication Type:Journal Article
- Keywords:
congenital hypodysfibrinogenemia;
gene sequencing;
fibrinogen aggregation assay;
bioinformatics
- From:
Chinese Journal of Clinical Laboratory Science
2025;43(2):92-97
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyse phenotype and genetic variation of two congenital hypodysfibrinogenemia(Fg)caused by compound heterozygous variants and preliminary investigate their molecular pathogenic mechanisms.Metheds The proband A and B and their family members(a total of 19 members in 3 generations)who visited the First Hospital of Wenzhou Medical University on 4 May 2023 and 20 May 2023 for"parkinson's disease"and"pre-bilateral eyelid excision"were enrolled for the study.Prothrombin time(TT)and fibrinogen(Fg)activity were measured by coagulation assay and Fg antigen(Fg∶Ag)was measured by immunoturbidimetric assay for the two family members,and Fg aggregation assay was catalysed using human thrombin.FGG gene was amplified by PCR and se-quenced directly.The variant sites were analysed using Chromas software.Multiple sequence comparison was performed by ClustalX-2.1-win software.Pathogenicity analysis of the variant sites was performed using bioinformatics software.The analysis for FGG protein model was performed using PyMOL software.Results Phenotypic results showed TT of proband A and B extended to 27.5 s and 26.1 s,and plasma Fg activity reduced to 0.6 g/L and＜0.5 g/L,respectively.Genetic sequencing identified heterozygous c.1129+62_65delAATA on intron 8 of FGG gene in the both probands,resulting in the formation of aberrant amino acids at p.γGly377-Gly388 and an early ter-mination codon at p.γTyr389 site.A heterozygous missense variant c.103C＞A(p.AαArg35Ser)was found in exon 2 of the FGA gene of proband A,and a heterozygous missense variant c.569A＞G(p.BβAsn190Ser)was found in exon 4 of the FGB gene of proband B.Compared to the control group,the both probands showed significant decreases in peak and rate of Fg aggregation.Multiple sequence comparison analyses showed that all the three variant sites were conserved.Three bioinformatics software predicted both the missense variants were pathogenic.Protein modelling analysis showed that the number of hydrogen bonds in p.γGly377-Gly388 variant region was altered,resulting in steric hinderance.Conclusion All the two types of compound heterozygous variants,i.e.,c.1129+62_65delAATA and p.AαArg35Ser,c.1129+62_65delAATA and p.BβAsn190Ser,have been reported for the first time in Chi-na and worldwide to date,and the three variants may be related to the reduced Fg level and function in the two pedigree.
