Clinical phenotype and genetic analysis of a case of haemophilia A in a newborn baby

Genetic analysis was conducted on a newborn with hemophilia A (HA) to identify the cause of the disease and conduct literature review. A retrospective analysis was conducted on the clinical manifestations of a newborn with HA. Whole exome sequencing (WES) technology was used to screen for pathogenic variants that matched the child's phenotype, and Sanger sequencing was performed to validate the patient, their mother, and half siblings. The clinical manifestations of the child were "subcapsular hematoma, head and face bruising, and progressive hemoglobin decline". A hemizygous frameshift deletion mutation on the coagulation factor Ⅷ (F8) gene was discovered in the patient: c.3637del: p.I11213Ffs * 5. This mutation caused the amino acid encoded by codon 1213 to change from isoleucine to phenylalanine, resulting in a frameshift and premature production of a stop codon. This mutation might lead to abnormal protein function. The mother and half sister of the child were both found to have a c.3637del: p.I11213Ffs*5 mutation in the F8 gene, which may be the cause of the child's illness. This mutation enriches the spectrum of F8 gene mutations and provides clues for genetic counseling and prenatal diagnosis of the family.