A study of JAK2 (V617F) gene mutation in patients with chronic myeloproliferative disorders.

BACKGROUND AND AIMS: Chronic myeloproliferative diseases (MPDs) are heterogenous group of haematological malignant disorders. It is now a well recognized fact that the JAK2 (V617F) mutation occurs in majority of the patients with polycythaemia vera (PV) and half of those with myelofibrosis and essential thrombocythaemia. The presence of JAK2 (V617F) mutation is considered an important criterion for the exclusion of secondary-reactive from clonal disorders. In the present uni-institutional study, we analyzed the JAK2 (V617F) mutation status in the ethnic Malay and Chinese patients who were diagnosed as MPDs. MATERIALS AND METHODS: The study was performed on known cases of chronic MPDs either at diagnosis or during the follow-up. A total of 45 cases were studied with informed consent. The allele specific PCR, ARMS-PCR and RQ-PCR methods were used. RESULTS: The frequency of the JAK2 (V617F) mutation varied between the MPD subtypes, with the mutation being most frequent in PV (95.8%) and 39% showed homozygous mutant allele. The mutation was detected in 52.9% cases of ET, of which 36.4% were homozygous for the mutant allele and 1 case of MF was homozygous for the mutant allele. CONCLUSION: Screening for the mutation in all cases suspected of chronic MPD could be beneficial in differentiating patients with reactive erthrocytosis or thrombocytosis from the true clonal MPDs especially polycythaemia vera.

G6PD enzyme activity in normal term Malaysian neonates and adults using a OSMMR2000-D kit with Hb normalization.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the commonest causes of neonatal jaundice in Malaysia. Screening of cord blood for G6PD deficiency by the semiquantitative fluorescent spot test (FST) is performed in Malaysia but this test can miss cases of partial G6PD deficiency. The OSMMR-D kit assay measures G6PD activity and hemoglobin (Hb) concentration, allowing direct expression of results in U/gHb. We evaluated this method and established the normal range for G6PD activity in normal term neonates and adults. EDTA blood from 94 neonates and 295 adults (age 15-59 years old) with normal Hb and FST were selected. The normal means for G6PD activity for neonates and adults were 12.43 +/- 2.28 U/gHb and 9.21 +/- 2.6 U/gHb, respectively; the reference ranges for normal G6PD activity in neonates and adults were 10.15-14.71 U/gHb and 6.61-11.81 U/gHb respectively. There were no significant differences in mean normal G6PD activity between the Malays and Chinese racial groups or between genders. The upper and lower limit cut-off points for partial deficiency in neonates were 7.4 U/gHb (60% of the normal mean) and 2.5 U/gHb (20% of the normal mean), respectively. For adults, the upper and lower limit cut-off points for partial deficiency in adults were 5.52 U/gHb (60% of the normal mean) and 1.84 U/gHb (20% of the normal mean), respectively. The quantitation of G6PD enzymes using this OSMMR-D kit with Hb normalization was simple since the Hb was analyzed simultaneously and the results were reproducible with a CV of less than 5%.