Female haemophilia A in a family with seeming extreme bidirectional lyonization tendency: abnormal premature X-chromosome inactivation?

We studied a female child with mild classical haemophilia A, presenting with a F VIII deficiency similar to that detected in her maternal grandfather. Investigations on several occasions showed that the obligate carrier mother of the proposita had normal VIII:C activity, whereas her likewise obligate carrier sister had a typical carrier VIII:C/vWf:Ag pattern. The child was a phenotypically normal female with normal karyotype. Her father had no clinical or biochemical signs of haemophilia A. RFLP-analysis using DX13 and St14 probes each elicited one allele (5.8 and 3.4 kb, respectively) segregating along with the affected F VIII gene from the hemizygous grandfather to both his daughters and further to the haemophilic female child. The paternity of the child was analyzed using various red cell and HLA antigens and RFLP by p29C, a probe detecting polymorphic hypervariable TaqI and PstI fragments in the pseudoautosomal areas of the X- and Y-chromosomes. All results obtained were concordant with the declared paternity. RFLP-analysis, using single (Pst I) and double digestion (Pst I/Hha I) of DNA and a PGK probe, revealed a remarkable difference in hybridization fragments, strongly suggesting hypermethylation, and in consequence, preferential X-chromosome inactivation in the proposita. This points to extreme lyonization as the most plausible explanation for haemophilia A in this female child. A familial tendency to abnormal premature X-chromosome inactivation is speculated.     

Haemophilia B- in a girl

Summary. Haemophilia B is extremely rare in females and so far 20 cases have been reported. A 9-year-old girl with severe haemophilia symptoms is described, who shows a very low level of factor IX activity (1.5%) and antigen (> 10%), normal XX female karyotype and negative family history of bleeding tendency or consanguinity. This case is probably the fourth report of sporadic female haemophilia B without chromosomal aberration and the first one with quantitative analysis by immunoradiometric assay and enzyme-linked immunosorbent assay of factor IX antigen. This very low factor IX level and severe bleeding tendency of the patient would be consistent with the homozygous state, but since a double mutation is extremely rare the patient's laboratory findings can be more easily explained by extreme lyonization of the normal X-chromosome of a heterozygous carrier.     

Prevalence of glucose-6-phosphate dehydrogenase deficiency in Northern Greece

Glucose-6-phosphate dehydrogenase (G6PD) deficiency affects more than 400 million persons worldwide. Its distribution varies significantly among different geographic regions and different population groups. Purpose of our study was to estimate its prevalence in Northern Greece. The dataset comprised 5161 newborns and adults who were screened for G6PD deficiency between July 2001 and March 2007. G6PD deficiency was detected by the dye reduction method. In the screened group, 6.3% of subjects were G6PD deficient. Moderate enzyme deficiency was shown in 139 individuals (2.7%). Complete deficiency was identified in 3.7%. The prevalence of G6PD deficiency in Northern Greece is much higher compared with the general Greek population. Moreover, G6PD prevalence in the male sex is much higher - almost double - that in the female sex.