F8 Gene Splice Donor Mutation (c.1271+1G>A) in Individual with Mild Hemophilia A in Indonesia: A Case Study

Hemophilia A is a bleeding disorder caused by a deficiency of coagulation factor VIII. Hemophilia A is an X-linked recessive disorder. Depending on the level of blood coagulation factor VIII, hemophilia severity is classified as mild (5-40%), moderate (1-5%), or severe (<1%). The absence of hemophilia A mutation studies in Indonesia makes this topic important to study.

This study detected and classified F8 gene mutations. A member of the Indonesian Hemophilia Society Association for the Special Region of Yogyakarta provided saliva for DNA testing. Long-read sequencing data were performed using the next-generation sequencing (NGS) technique via the Oxford Nanopore Technologies plc (ONT) PromethION 24 platform. The mutation was confirmed using Sanger sequencing, after amplifying intron 8 of the F8 gene with the PCR technique. The F8 gene intron 8 nucleotide sequence was aligned using the alignment tool on the Benchling website.

The results of this study showed that there was a splice donor site mutation in intron 8 of the F8 gene (c.1271+1G>A) in one patient. This mutation can cause the occurrence of cryptic splice donor sites. Cryptic splice donor site prediction was carried out using the splice donor prediction tool available on the NNSPLICE website. The appearance of cryptic splice donor sites can lead to the formation of out-of-frame proteins.

The F8 gene mutation causing hemophilia A was detected using long-read sequencing and the next-generation sequencing (NGS) technique. The type of mutation identified is a splice donor site mutation, specifically the variant c.1271+1G>A, in sample code HM13.