Haemophilia A in a Female: Study of a Family Using Intragenic and Extragenic Restriction Site Polymorphisms

Three-Decade Successive Establishment of Care for Women/Girls from Families with Haemophilia

Objective

The study aimed to report a 3-decade successive establishment of care for women/girls from families with haemophilia.

Methods

A retrospective analysis was conducted on 462 women/girls from 243 families from 1987 to 2021.

Results

Combining phenotypic analysis of coagulation factor and genotypic analysis of either linkage analysis or mutation detection confirmed the status of all obligate haemophilia carriers (A118, B19). For potential carrier, 159 proven carriers (A130, B29) and 146 noncarrier status (A126, B20) were diagnosed except 20 potential carriers (A16, B4). Only 54 prenatal diagnoses were requested resulting in normal males (n = 21), males with haemophilia A (n = 12) and females with either normal or carrier status (n = 21). Additionally, 40 women/girls with haemophilia carrier received a diagnosis of severe haemophilia A with Turner’s syndrome (n = 2) and mild haemophilia (A31, B7). The skewed X-chromosome inactivation of the nonmutant factor VIII/IX carrying X-chromosome of 8% (2/25) was found in mild haemophilia. Factor concentrate and desmopressin are prescribed for these affected women/girls. The response of women/girls with either haemophilia carrier or haemophilia was amazement with their religious beliefs and cultural acceptance.

Conclusion

Appropriate care for women/girls from families with haemophilia concerning diagnosis and management of haemophilia and carrier has been successively established.

Unbalanced X-chromosome inactivation with a novel FVIII gene mutation resulting in severe hemophilia A in a female

This report is of a 14-month-old girl affected with severe hemophilia A. Both her parents had normal values for factor VIII activity, and von Willebrand disease type 2N was excluded. Karyotype analysis demonstrated no obvious alteration, and BclI Southern blot did not reveal F8 gene inversions. Direct sequencing of F8 gene exons revealed a frameshift-stop mutation (Q565delC/ter566) in the heterozygous state in the proposita only. F8 gene polymorphism analysis indicated that the mutation must have occurred de novo in the paternal germline. Furthermore, analysis of the pattern of X chromosome methylation at the human androgen receptor gene locus demonstrated a skewed inactivation of the derived maternal X chromosome from the lymphocytes of the proband's DNA. Thus, the severe hemophilia A in the proposita results from a de novo F8 gene frameshift-stop mutation on the paternally derived X chromosome, associated with a nonrandom pattern of inactivation of the maternally derived X chromosome.

Unbalanced X-chromosome inactivation with a novel FVIII gene mutation resulting in severe hemophilia A in a female

This report is of a 14-month-old girl affected with severe hemophilia A. Both her parents had normal values for factor VIII activity, and von Willebrand disease type 2N was excluded. Karyotype analysis demonstrated no obvious alteration, and BclI Southern blot did not reveal F8 gene inversions. Direct sequencing of F8 gene exons revealed a frameshift-stop mutation (Q565delC/ter566) in the heterozygous state in the proposita only. F8 gene polymorphism analysis indicated that the mutation must have occurred de novo in the paternal germline. Furthermore, analysis of the pattern of X chromosome methylation at the human androgen receptor gene locus demonstrated a skewed inactivation of the derived maternal X chromosome from the lymphocytes of the proband's DNA. Thus, the severe hemophilia A in the proposita results from a de novo F8 gene frameshift-stop mutation on the paternally derived X chromosome, associated with a nonrandom pattern of inactivation of the maternally derived X chromosome.

Severe haemophilia A in a female: a compound heterozygote with nonrandom X-inactivation

We report a case of severe haemophilia A (<1% factor VIII level) in a female resulting from an interesting and improbable combination of events. The patient inherited a factor VIII intron 22 inversion from her carrier mother, as well as a second factor VIII inversion involving intron 22 that arose de novo on her paternally derived X chromosome. In addition, the patient's paternally derived X chromosome had been preferentially inactivated in 95+% of her somatic cells. The patient's mother, who was clinically unaffected, carried an intron 22 inversion as well and also showed nonrandom X-inactivation. The patient's mother had a brother with severe haemophilia A. It is therefore likely that the mother's inversion was on her maternally derived X chromosome. Since she was unaffected, it is likely that her inversion-bearing X was the one that was preferentially inactivated.

Hemophilia B in a female carrier due to skewed inactivation of the normal X-chromosome

A novel missense mutation (codon 351, GCT (Ala) --> CCT (Pro)) of the FIX gene was characterised in a young female with mild hemophilia B. She is heterozygous for the FIX mutation inherited from her carrier mother. Analysis of the methyl-sensitive Hpa II sites at the 5' end of the hypoxanthine phosphoribosyltransferase gene showed that skewed inactivation of the X chromosome carrying her normal FIX gene accounted for the hemophilia phenotype.