Haemophilia B in a female caused by skewed inactivation of the normal X-chromosome.
Hemophilia B (factor IX deficiency) is an X-linked recessive disorder with a prevalence of 1:30,000 male births, which rarely affects females. A missense mutation T38R (6488C>G) of the factor IX (FIX) gene was characterized in a young female with moderate-to-severe hemophilia B. She is heterozygous for this mutation, which she inherited from her carrier mother. Analysis of the methyl-sensitive HpaII sites in the first exon of the human androgen-receptor locus indicated a de novo skewed X-chromosomal inactivation. This indicates that the paternal X-chromosome carrying her normal FIX gene is the inactive one, which has led to the phenotypic expression of hemophilia B in this patient.
Espinós
C
C
Unidad de Coagulopatías Congénitas, Hospital Universitario La Fe. Avd. de Campanar, 21. 46009 Valencia, Spain. espinos@uv.es
Lorenzo
J I
JI
Casaña
P
P
Martínez
F
F
Aznar
J A
JA
D004303:Dosage Compensation, Genetic; D005260:Female; D002836:Hemophilia B / Q000150:complications / Q000209:etiology / Q000235:genetics* / Q000628:therapy; D006801:Humans; D007223:Infant; D016040:Lung Transplantation; D008297:Male; D010375:Pedigree; D011516:Prothrombin / Q000627:therapeutic use; D011658:Pulmonary Fibrosis / Q000209:etiology / Q000601:surgery
D011516:Prothrombin