The Italian AICE-Genetics hemophilia A database: results and correlation with clinical phenotype.
BACKGROUND
The high mutational heterogeneity of hemophilia A is a challenge for the provision of genetic services. We plan to identify the mutation in patients with hemophilia A in order to create a confidential national database of mutations for the optimization of genetic services in Italy.


METHODS
The factor VIII gene (F8) was analyzed in 1296 unrelated patients with hemophilia A using screening methods for intron 22 and 1 inversions and rare mutations (denaturing high performance liquid chromatography, conformation sensitive gel electrophoresis) and/or direct sequencing.


RESULTS
F8 mutations were identified in 874 (89%), 146 (89%), and 133 (94%) families with severe, moderate, or mild hemophilia A, respectively. Mutations predicting a null allele were responsible for 80%, 15%, and less than 1% of cases of severe, moderate, or mild hemophilia A, respectively. About 40% of missense and nonsense mutations occurred at a CpG site, arginines being most frequently affected. Of the small deletions or insertions, 29% occurred at one of two stretches of adenines, codons 1191-1194 (8As) and 1439-1441 (9As). Overall, these "hotspots" accounted for 31% of the point mutations in the patients with hemophilia A. Inhibitors developed in 22% of the patients with severe hemophilia A, 8% of those with moderate disease and in 4% of patients with mild hemophilia A. Patients who had severe hemophilia A and mutations predicting a null allele developed inhibitors more frequently (22 to 67%) than patients with missense mutations (5%).


CONCLUSIONS
We report a wide spectrum of mutations in a large national database. The type of mutation was a strong predictor of the clinical phenotype. This database is expected to considerably improve the genetic counselling and medical care of families with hemophilia A in Italy.
Margaglione
Maurizio
M
Cattedra di Genetica Medica, Dipartimento di Scienze Biomediche, Università degli Studi di Foggia, viale Pinto, 71100 Foggia, Italy. m.margaglione@unifg.it
Castaman
Giancarlo
G
Morfini
Massimo
M
Rocino
Angiola
A
Santagostino
Elena
E
Tagariello
Giuseppe
G
Tagliaferri
Anna Rita
AR
Zanon
Ezio
E
Bicocchi
Maria Patrizia
MP
Castaldo
Giuseppe
G
Peyvandi
Flora
F
Santacroce
Rosa
R
Torricelli
Francesca
F
Grandone
Elvira
E
Mannucci
Pier Mannuccio
PM
D019774:Blood Coagulation Factor Inhibitors / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003062:Codon; D004252:DNA Mutational Analysis; D030541:Databases, Genetic; D005169:Factor VIII / Q000235:genetics*; D005838:Genotype; D006467:Hemophilia A / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D007438:Introns; D007558:Italy; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D012042:Registries
D019774:Blood Coagulation Factor Inhibitors; D003062:Codon; D005169:Factor VIII