Prevalence of G-6-PD deficiency in the Croatian Adriatic Coast population

Molecular Characterization of Glucose-6-phosphate Dehydrogenase Deficiency in Families from the Republic of Macedonia and Genotype-phenotype Correlation

Introduction:

Glucose-6-phospahte dehydrogenase deficiency (G6PD) is one of the most common inherited disorders affecting around 400 million people worldwide. Molecular analysis of the G6PD gene identified more than 140 distinct mutations, the majority being single base missense mutations. G6PD Mediterranean is the most common variant found in populations of the Mediterranean area.

Aim:

The aim of our study was to perform molecular characterization of G6PD deficiency in families from the Republic of Macedonia and correlate the findings to disease phenotype.

Patients and methods:

Six patients and seven other family members were selected for genetic characterization, the selection procedure involved clinical evaluation and G6PD quantitative testing. All patients were first screened for the Mediterranean mutation, and subsequently for the Seattle mutation. Mutations were detected using PCR amplification and appropriate restriction endonuclease cleavage.

Results:

Four hemizygote and 3 heterozygous carriers for G6PD Mediterranean were detected. All G6PD deficient patients from this group showed clinical picture of hemolysis, and in 66.6% neonatal jaundice was confirmed based on history data. To our knowledge, this is the first study concerned with molecular aspects of the G6PD deficiency in R. Macedonia.

Conclusion:

This study represents a step towards a more comprehensive genetic evaluation in our population and better understanding of the health issues involved.

Evaluation of Neonatal Hemolytic Jaundice: Clinical and Laboratory Parameters

BACKGROUND:

Neonatal jaundice that occurs in ABO or Rhesus issoimunisation has been recognized as one of the major risk factors for development of severe hyperbilirubinemia and bilirubin neurotoxicity.

AIM:

Aim of our study was to investigate clinical and laboratory parameters associated with hemolytic jaundice due to Rh and ABO incompatibility and compare results with the group of unspecific jaundice.

MATERIAL AND METHODS:

One hundred sixty seven (167) neonatal hyperbilirubinemia cases were included in the study, 24.6% of which presented with ABO/Rhesus type hemolytic jaundice, and the rest with unspecific jaundice. Evaluation included: blood count, reticulocites, serum bilirubin, aminotransferases, blood grouping, and Coombs test, also the day of bilirubin peak, duration of the hyperbilirubinemia, and additional bilirubin measurements.

RESULTS:

We showed significantly lower mean values of hemoglobin, erythrocytes and hematocrit and significantly higher values of reticulocytes in the group of ABO/Rh incompatibility compared to the group of jaundice of unspecific etiology; also an earlier presentation and a higher-grade jaundice in this group.

CONCLUSIONS:

The laboratory profile in ABO/Rh isoimmunisation cases depicts hemolytic mechanism of jaundice. These cases carry a significant risk for early and severe hyperbilirubinemia and are eligible for neurodevelopmental follow-up. Hematological parameters and blood grouping are simple diagnostic methods that assist the etiological diagnosis of neonatal hyperbilirubinemia.

Glucose-6-phosphate dehydrogenase deficiency and idiopathic presenile cataract in Dalmatia, Croatia

BACKGROUND

Impaired activity of the enzyme glucose-6-phosphate dehydrogenase (G6PD) has been suggested as a risk factor in cataractogenesis. The aim of this study was to determine the G6PD activity level in 89 male subjects of Dalmatian origin with idiopathic presenile cataracts.

METHODS

G6PD activity was determined by a quantitative spectrophotometric method.

RESULTS

Of 89 males with presenile cataracts only one (1.1%) had G6PD deficiency. The G6PD deficiency prevalence rate among males with presenile cataracts is not significantly different (p > 0.05) from the prevalence of G6PD deficiency in the general population of Dalmatia (0.75% among men).

INTERPRETATION

The results of this study suggest that G6PD deficiency does not represent a pathogenetic factor in presenile cataract, at least not in the population of the southern part of Croatia.

Prevalence of Erythrocyte Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency in the Population of Western Turkey

BACKGROUND

Newborn G6PD deficiency screening has been recognized as an essential component of public health care in most developed and some Mediterranean countries. However, such screening is yet to be widely embraced in Turkey. The aim of the present study was to determine the normal values of G6PD and deficiency prevalence of this enzyme in different age groups of people living in the western region of Turkey and accordingly inform and educate about favism to those asymptomatic carriers who usually are not aware of their G6PD deficient status.

METHODS

A total of 1421 clinically healthy individuals without evidence of leukocytosis or thrombocytosis were included in the study. Activity of G6PD was quantitatively measured.

RESULTS

Normal mean values of G6PD in healthy males were 8.94 +/- 8.65 IU/g Hb (or 231.73 +/- 43.16 IU/10(12) RBC), in females were 9.16 +/- 3.78 IU/g Hb (or 219.9 +/- 43.1 IU/10(12) RBC). The frequencies of severe and mild G6PD deficiencies were 0.44% and 6.07% in females, respectively, whereas in males it was 7.24%. Overall frequency of the G6PD-deficient phenotype was detected as 6.9%.

CONCLUSIONS

There is no significant statistical difference of G6PD activity between males and females, although frequency of the G6PD-deficient phenotype is relatively high in western Turkey. The results emphasize a need for screening for G6PD deficiency before prescribing anti-malarial therapy with drugs like primaquine to patients in this region of Turkey known for its prevalence of malaria.

Characterization of G6PD deficiency in southern Croatia: description of a new variant, G6PD Split

Glucose-6-phosphate dehydrogenase (G6PD) deficiency protects from severe forms of malaria. It is interesting therefore to analyze the molecular basis underlying G6PD deficiency in regions such as the Mediterranean basin where malaria was present for a long time in history. Here we report on the genetic characterization of G6PD deficiency among inhabitants of one Mediterranean region-the Dalmatian region of south Croatia. We analyzed 24 unrelated G6PD-deficient male subjects. Molecular testing revealed several different mutations: G6PD Cosenza 9, G6PD Mediterranean 4, G6PD Seattle 3, G6PD Union 3, and G6PD Cassano 1. Furthermore, we have identified one novel G6PD variant that we named G6PD Split. This variant is caused by a nucleotide change 1442 C-->G leading to the amino acid substitution 481 Pro-->Arg and is characterized by moderate enzyme deficiency (class III variant). This study reveals a higher prevalence (37.5%) of the Cosenza mutation in the Dalmatian region than anywhere else previously investigated and overall shows the considerable molecular heterogeneity underlining G6PD deficiency that can be observed in Mediterranean populations.

Prevalence of factor V Leiden and G6PD 1311 silent mutations in Dalmatian population

BACKGROUND

Factor V Leiden has been described as a common genetic risk factor for venous thromboembolism. The geographic distribution of this abnormality varies greatly, being high in Europe and almost absent in Asia and Africa. Particularly high prevalence is observed in some Mediterranean countries, which suggests the Mediterranean origin of this mutation. Similarly, prevalence of silent mutation 1311 of the G6PD gene seems to be higher among Mediterranean populations. Since the Dalmatian population (of south Croatia) geographically belongs to the Mediterranean populations we analyzed the prevalence of FV-Leiden and silent mutation 1311 in this region. Furthermore, because the coincidence of G6PD deficiency and venous thromboembolism was described earlier, we tested a possible association of FV-Leiden and G6PD deficiency.

METHODS

One hundred sixty-eight healthy blood donors and 55 G6PD deficient individuals originating from the Dalmatian region were tested for the presence of FV-Leiden mutation and silent mutation 1311.

RESULTS

Prevalence of FV-Leiden among blood donors was 2.4%, while among G6PD deficient individuals it was significantly higher, 11% (p=0.011). Prevalence of silent mutation 1311 among blood donors and G6PD deficient individuals was 21 and 15%, respectively.

CONCLUSIONS

Observed allele frequencies among individuals originating from the Dalmatian region is similar to the neighboring European and Mediterranean populations. Interestingly, our results indicate the association of the FV-Leiden and G6PD deficiency and warrant further studies.

Glucose-6-phosphate dehydrogenase partitioning in two-phase aqueous mixed (nonionic/cationic) micellar systems

The enzyme glucose-6-phosphate dehydrogenase (G6PD) plays an important role in maintaining the level of NADPH and in producing pentose phosphates for nucleotide biosynthesis. It is also of great value as an analytical reagent, being used in various quantitative assays. In searching for new strategies to purify this enzyme, the partitioning of G6PD in two-phase aqueous mixed (nonionic/cationic) micellar systems was investigated both experimentally and theoretically. Our results indicate that the use of a two-phase aqueous mixed micellar system composed of the nonionic surfactant C(10)E(4) (n-decyl tetra(ethylene oxide)) and the cationic surfactant C(n)TAB (alkyltrimethylammonium bromide, n = 8, 10, or 12) can improve significantly the partitioning behavior of G6PD relative to that obtained in the two-phase aqueous C(10)E(4) micellar system. This improvement can be attributed to electrostatic attractions between the positively charged mixed (nonionic/cationic) micelles and the net negatively charged enzyme G6PD, resulting in the preferential partitioning of G6PD to the top, mixed micelle-rich phase of the two-phase aqueous mixed micellar systems. The effect of varying the cationic surfactant tail length (n = 8, 10, and 12) on the denaturation and partitioning behavior of G6PD in the C(10)E(4) /C(n)TAB/buffer system was investigated. It was found that C(8)TAB is the least denaturing to G6PD, followed by C(10)TAB and C(12)TAB. However, the C(10)E(4)/C(12)TAB/buffer system generated stronger electrostatic attractions with the net negatively charged enzyme G6PD than the C(10)E(4)/C(10)TAB/buffer and the C(10)E(4)/C(8)TAB/buffer systems, when using the same amount of cationic surfactant. Overall, the two-phase aqueous mixed (C(10)E(4)/C(10)TAB) micellar system yielded the highest G6PD partition coefficient of 7.7, with a G6PD yield in the top phase of 71%, providing the optimal balance between the denaturing effect and the electrostatic attractions for the three cationic surfactants examined. A recently developed theoretical framework to predict protein partition coefficients in two-phase aqueous mixed (nonionic/ionic) micellar systems was implemented, and the theoretically predicted G6PD partition coefficients were found to be in reasonable quantitative agreement with the experimentally measured ones.