Abstract
Abstract 3162
Background:
Hemophilia is a hereditary bleeding disorder manifested by prominent bleeding in the musculoskeletal system. Patients with severe and moderate severity require life long administration of factor concentrates to replace the missing coagulation factors, otherwise they may end-up with morbidity and mortality in the early childhood period.
Objective:
To set-up carrier detection and prenatal diagnosis service for hemophilia all over Thailand.
Methods:
A study of DNA extraction from EDTA blood sent by surface mail without ice was previously conducted and revealed that the quality and quantity of extracted DNA from EDTA blood was suitable for the genotypic analysis of hemophilia up to 10 days of transportation. Then, the managers who are nurses in 42 registered hemophilia treatment centers located at the provincial, regional and university hospitals all over Thailand attended a two-day short course training on genetic counseling. They learned the clinical aspect of hemophilia, mode of inheritance and identify females at risk for carrier, writing a pedigree, preparing the blood samples, and sending them to the comprehensive hemophilia treatment center in Bangkok.
Results:
After the accurate diagnosis of moderate or severe hemophilia, genetic counseling was provided by a well-trained health personnel in the comprehensive hemophilia center in Bangkok or their hometown. A ‘family genetic game’ was created and used for the counseling. It consisted of pictures of father, mother, sons, daughters, normal X chromosome, X chromosome with hemophilia gene, and normal Y chromosome. A magnet was attached to the back of every individual piece of picture. Different scenarios were demonstrated and discussed interactively. After the family members clearly understood their own risk of being a hemophilia carrier, the nurse took their blood with EDTA anticoagulant and sent to the comprehensive hemophilia center in Bangkok by surface mail without ice. Genotypic analysis of hemophilia A and B family was performed by screening the mutation with the conformation gel electrophoresis followed by sequencing except for those with hemophilia A families, the inversion of intron 22 was initially performed. Also, polymorphisms associated with factor VIII gene (Bcl I, intron 13, intron 22) and factor IX gene (Mse I, Sal I, Nru I, Dde I, Hha I) among the patients and family members were also studied. A pilot study was conducted in 151 patients from 140 families (101 hemophilia A, 39 hemophilia B). For hemophilia A, the inversion of intron 22 was found in 46 families, 19 with identified mutations and 36 on the process of mutation identification. On the contrary, mutations were identified in all 39 families with hemophilia B. Nine novel mutations were found in hemophilia A (p.Asp2108 Val fs*15, p.Ser853*, p.Met1934 fs, p.Leu529Asp fs*6, p.Trp637*, p.Ala469Pro, p.Arg1966*, p.Trp208*, p.Asn1441Ile*5) and 6 novel mutations were found in hemophilia B (p.Trp194Ser, p.Gly317Arg, p.Asp359 Val, p.Gln-45 fs, p.Glu-37 fs, p.Tyr69 fs). Eighty females at risk for carrier were included and half of them were diagnosed with carriers. However, 26 prenatal diagnosis was performed in 21 females (18 hemophilia A, 3 hemophilia B) by chorionic villi sampling, amniocentesis or fetal blood sampling. The results revealed 23 male and 3 female fetuses. Only six male fetuses were diagnosed with hemophilia and the pregnancies were terminated due to the request of the couples at risk. An additional termination of pregnancy was performed in one male fetus with Down syndrome. Only one fetal loss complication was found.
The cost of genotypic analysis for each family and the prenatal diagnosis was 100 USD and 75 USD, respectively. Therefore, the total cost of this pilot study was 15,950 USD and six births of new hemophilia patient were prevented. It is highly cost-effective as compared to the cost of treatment. Importantly, the established service is convenient for family members even though they stay far from the advanced comprehensive hemophilia center.
Conclusion:
A service for carrier detection and prenatal diagnosis is essentially. required for developing countries where adequate treatment of factor concentrates is not available. It should be integrated into the existing infrastructure of health care system. Research for simplifying the advanced technology and training for upgrading the medical knowledge among health personnel are the keys of success.
Disclosures:
No relevant conflicts of interest to declare.
Hemophilia A: carrier detection and prenatal diagnosis by DNA analysis