New and known ß-thalassemia determinants masked by known and new δ gene defects [Hb A(2)-Ramallah or δ6(A3)Glu→Gln, GAG>>CAG].

We report a novel thalassemia determinant found in a Nigerian woman living in the Netherlands, resulting from a 2 bp insertion at codons 9/10 of the ß-globin gene (HBBc.28_29insTA p.Ser10LeufsX11). The novel defect causes a frameshift with a consequent premature TGA stop codon, located at 11 positions downstream from the mutated codon. The phenotype was typical of a ß-thalassemia (ß-thal), trait with high RBC counts and compensated mild microcytic anemia. However, the Hb A(2) level was reported to be normal due to the presence of the common Hb A(2)' or Hb B2 [δ16(A13)Gly→Arg, GGC>CGC] variant that was not taken into account. We also present the opposite but comparable situation found in an a Palestinian man living in the USA. He was a carrier of a common ß-globin gene defect [codon 6 (-A), HBB:c.20delA] in combination with a novel δ-globin gene defect at codon 6 [HBD. c.19G>C, Glu6Gln] that we have named Hb A(2)-Ramallah. In both cases, the provisional diagnosis could have been compromised when based on the measurement of the normal Hb A(2) fraction only.

The influence of acetylsalicylic acid intake by healthy volunteers on duplicate PFA-100 measurements.

The PFA-100 device is increasingly used for assessing platelet function. Its use to monitor anti-platelet therapy, like acetylsalicylic acid (ASA), has been described. In most studies single PFA-100 measurements were used. In this study, we evaluate the influence of ASA on duplicate measurements using collagen/epinephrine cartridges. Twelve healthy volunteers received a single dose of 160 mg ASA and 12 other healthy volunteers received 30 mg ASA during 10 days followed by 80 mg ASA during 10 days. PFA-100 measurements were performed in duplicate 1 and 24 h after the final intake of medication. The mean coefficient of variation of duplicate measurements before medication was 8.4% and at least two times higher after the intake of a single dose of 160 mg ASA or 30 mg ASA during 10 days. Per individual, huge differences between duplicate measurements were observed after ASA ingestion. Differences were less pronounced after ingestion of 80 mg ASA during 10 days, because six of 12 volunteers had a maximum PFA-100 value>300 s in both measurements. As a consequence, one should be cautious to use the PFA-100 to monitor ASA therapy in individual patients.

A novel C2 transferrin variant interfering with the analysis of carbohydrate-deficient transferrin.

BACKGROUND: Carbohydrate-deficient transferrin (CDT) is used as a marker for chronic alcohol abuse. The presence of genetic transferrin variants might affect an individual's iron status and can interfere with CDT analysis. We report on the identification of a patient carrying a novel transferrin variant. We describe the performance of the various CDT methods in its detection and the associated iron status. METHODS: DNA of the coding region of transferrin was sequenced and CDT levels were analysed using four different methods: high pressure liquid chromatography (HPLC), capillary zone electrophoresis (CZE), immunochemistry and iso-electric focussing (IEF). RESULTS: A novel transferrin variant, T139M, was found as a heterozygous genotype in the index patient and all of his four living direct family members (c.416C>p.Thr139Met). CDT analysis of the variant by HPLC and CZE was compromised as a result of the coelution of the different isoforms. CDT levels could be quantified by immunochemistry. Similar results were obtained using IEF analysis. The presence of the C2 transferrin variant did not affect iron status in any of the investigated patients. CONCLUSIONS: Transferrin T139M, present as a heterozygous genotype, interferes with CDT analysis by HPLC and CZE but not by immunochemistry. Physiologically, it appears to be functionally normal.