In this study, the authors reported the case of homozygous combined hereditary deficiency of FVII and FX. The proband was a 16-yr-old Chinese man without a personal history of bleeding. The patient was admitted to hospital due to accidental ingestion of a diphacinone rodenticide. Routine coagulation screening tests revealed a prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT) and low levels of vitamin K-dependent coagulation factors (FII, FVII, FIX and FX) activity. After three months of vitamin-K1 treatment, FII and FIX coagulation activity (FII:C and FIX:C) were in the normal range while FVII and FX activity (FVII:C and FX:C) were still very low. This led to hypothesise the existence of combined congenital deficiency in FVII and FX. Upon analysis, direct sequencing revealed two homozygous mutations, c.1009C>T in exon 8 of FVII resulting in p.Arg277Cys and c.1270G>T in exon 8 of FX leading to p.Val384Phe. Notably, both the pro-band’s parents and sister were heterozygous for p.Arg277Cys and p.Val384Phe mutations. The authors concluded that the findings suggest that when investigating rodenticide intoxication, reconsideration is needed if data are confusing and genetic studies may supply further useful information.
Authors: Zheng, Fangxiu; Jin, Yanhui; Wang, Mingshan; Niu, Zhenzhen; Xu, Pengfei; Xie, Haixiao ;Full Source: Thrombosis and Haemostasis 2011, 106(1), 180-181 (Eng) ;