Screening of mutations of hemophilia A in 40 Italian patients: a novel G-to-A mutation in intron 10 of the F8 gene as a putative cause of mild hemophilia a in southern Italy

Abstract

Hemophilia A is an X-linked bleeding disorder caused by widespread mutations in the human coagulation factor 8 gene. We have searched for mutations in factor 8 gene DNAs from 40 unrelated Italian patients with hemophilia A. All patients came from the same region (Calabria) and were followed-up at the same hemophilia center. Of the 40 patients, 20 (50%) had severe hemophilia A, 19 (47.5%) had moderate hemophilia A, and one (2.5%) had mild hemophilia A. All patients were first screened for the common intron 22 and intron 1 inversions. Inversion-negative samples were screened for point mutations by direct sequencing of all coding regions and intron-exon boundaries of the factor 8 gene. Mutations previously reported as causative of hemophilia A were identified in 14 of the 40 patients. These included five (12.5%) intron 22 inversions, one (2.5%) small deletion, one (2.5%) small insertion and seven (17.5%) point mutations. In all patients with moderate and mild hemophilia A, a nucleotide change in the c.1538 -18G>A in intron 10, not reported in the HAMSTeRS factor 8 mutation database (http://europium.csc.mrc.ac.uk/), was found. The G-to-A change predicts the appearance of a new acceptor splice site. We have also demonstrated that all patients share a common haplotype, suggesting that the mutation probably occurred in a single ancestor. In conclusion, we suggest that the c.1538-18G>A transition can be the putative mutation, which probably occurred in a common ancestor and then spread in neighbours, in patients with moderate-mild hemophilia A investigated in the present study.

Molecular genotyping of hemophilia A in Saudi Arabia: report of 2 novel mutations

“…This work is considered to be the first attempts to establish a diagnostic laboratory molecular approach for hemophilia A genotype in the Saudi population. In this study, 22 hemophilia patients from 18 unrelated families were subjected to F8 molecular analysis following clinical examination, the study confirmed that F8 intron 22 inversion is the most common genetic abnormality of hemophilia A in Saudi Arabia representing 50% of severe cases, which was little more than previously reported [14,15] and much less than other reports from various world regions [16,17]. In our cohort we did not screen for other inversions like intron 1.…”

“…We detected a novel mutation R593P in three patients affected with a severe form of hemophilia A. Although mutations in this codon were previously reported, including one reported recently by one of our collaboration [2,14]. Yet, the reported mutation in our study involves the substitution of the hydrophilic positive charged arginine (R) with a hydrophobic proline (P), which was not reported previously in F8 HAMSTeRS and HGMD databases.…”

F8 mRNA studies in haemophilia A patients with different splice site mutations

“…The c.1538 −18 G>A mutation in intron 10 has been reported very recently in a population of mild‐moderate HA patients from Southern Italy [7]. In silico analysis with http://www.fruitfly.org/seq_tools/splice.html and http://www.umd.be/HSF/ predicted the inclusion of 16 nucleotides of intron 10 within the coding region.…”

Overrepresentation of missense mutations in mild hemophilia A patients from Belgium: founder effect or independent occurrence?

“…However, several publications have described F8 mutations that are highly prevalent in specific populations sharing the same haplotype, indicating the existence of a single, common ancestor. Examples of this can be seen with the c.6104 T N C or p.Val2035Alanine (legacy AA No.2016) mutation, identified in an isolated population in rural Newfoundland [14], the exon 13 duplication located in northern Italy [1], and the novel Gto-A mutation (c.1538-18G N A) in intron 10 of the F8 gene, which was identified as a putative cause of mild hemophilia A in southern Italy [13]. All these mutations were associated with the mild HA phenotype.…”