Increased Prevalence of Glucose-6-Phosphate Dehydrogenase Deficiency in Patients with Cholelithiasis

by

T. Meloni a , G. Forteleoni a , G. Noja b , G.. Dettori b , M.A. Sale b , G.F. Meloni a


a Clinica Pediatrica 'A. Filia' Università, b Clinica Chirurgica Università, Sassari, Italia
Key Words.
Cholelithiasis, Gallstones, Glucose-6-phosphate dehydrogenase deficiency

Abstract
The glucose-6-phosphate dehydrogenase (G6PD) enzyme activity was determined in 299 Northen Sardinian patients with cholelithiasis. Sixteen (12,80%) of the 1125 male patients studied were G6PD deficient; 33 (18.96%) of the 174 females were heterozygous and 1 (0,57%) homozygous. Thus, the prevalence of G6PD deficiency in male subjects with cholelithiasis is about 35% higher (p < 0.02) than that of a normal male control group (7.29%). As regards female patients, the incidence of the GdMed allele was also significantly different (p < 0.05). Thus, G6PD-deficient subjects may have a predisposition to develop gallstones, even in the absence of clinical signs of chronic hemolysis.


Cholelithiasis is a very common disease, the frequency of which increases with age. The bilirubin type of gallstones is frequently observed in patients with chronic hemolytic anemia. Cholelithiasis develops in a high percentage (about 40%) of subjects with glucose-6-phosphate dehydrogenase (G6PD) deficiency and chronic hemolytic anemia [1]; this phenomenon has been attributed to the accelerated red cell turnover. Since the half-life of 51Cr-labeled red cells diminished even in G6PD-deficient subjects without chronic hemolytic anemia [2], we have investigated whether the increased red cell turnover is associated with a higher frequency of cholelithiasis in G6PD deficient subjects.

Materials and Methods
The study included 125 males and 174 females of Northern Sardinian origin, aged 21-86 years, who underwent surgery for cholelithiasis from May 1984 to December 1988. G6PD activity was tested in males as described by Battistuzzi et al. [3]. Determination of G6PD mosaicism in females was hased on the 2-deoxy-glucose-6-phosphate (2dG6P) utilization in mononuclear cells, according to the method described by Ferraris et al. [4] and Gaetani et al. [5]. This technique permits accurate determination of the degree of G6PD mosaicism in various hemopoietic cell populations.

A complete blood cell count, including the percentage of reticulocytes, was performed in all patients.

The stone composition was analyzed in 12 G6PD-deficient subjects and in 35 control patients with cholelithiasis.

Epidemiological data on the frequency of G6PD deficiency in normal males of Northern Sardinian origin were derived from the screening campaign for the prevention of favism, which was carried out in 1977-1978, using the method of Battistuzzi et al. [3]; 1,646 males, aged 8-60 years and coming from the same geographical area as the patients with cholelithiasis, were tested and 120 (7.29%) proved to be G6PD deficient [T. Meloni, unpublished data].

The frequency of enzyme deficiency in normal females, considering the high percentage of false-negative results using either the spectrophotometric or methemoglobin reduction test, was estimated from the frequency observed in males, according to the Hardy-Weinberg law.

Results
Blood cell counts and reticulocytes from all patients were within normal limits.

Stones were composed of cholesterol in all control subjects, whereas 10 out of 12 stones from G6PD-deficient subjects were shown to be composed of bilirubin (the remaining 2 were also cholesterol stones).

Sixteen (12.80%) of the 125 male patients studied were G6PD deficient (Mediterranean variant). Thirty-three (18.96%) of the 174 female patients examined showed a 2dG6P utilization between 7.96 and 23.40%, and were classified as G6PD B/ G6PD Mediterranean heterozygous; 1 (0.57%) showed a 2dG6P utilization of 33% and was thus classified as a G6PD Mediterranean homozygous. The prevalence of G6PD deficiency in subjects with cholelithiasis (12.80%) was approximately a third higher than in normal males (table 1), in whom the frequency of G6PD deficiency is 7.37%. Statistical analysis of the data using the (2 test revealed a highly significant difference between the values expected and those found in the study group (p < 0.02).

 


Table 1. Observed frequencies of G6PD deficiency in male patients with cholelithiasis vs. frequencies in the normal male population of Northern Sardinia

 

Observed Normal male population
n % n %
Normal 109 87.20 1526 92.71
G6PD deficient 16 12.80 120 7.29
Total 125 100.00 1646 100.00

 


As regards female patients (table 2), the prevalence of G6PD deficiency was 19.54% (including heterozygotes and homozygotes), which is higher than the value expected according to the Hardy-Weinberg law (14.2%). The c 2 test showed a significant difference , (p < 0.05), though lower than that observed in males.

 


Table 2. Observed frequencies of G6PD genotypes in female patients with cholelithiasis vs. expected frequencies (calculated according to the Hardy-Weinberg Law)

 

Observed Expected, %
n %
Normal 140 80.46 85.95
G6PD heterozygotes 33 19.97 13.52
G6PD homozygotes 1 0.57 0.53
Total 174 100.00 100.00

 


The patients were further subdivided into 5 age groups: under 40, 41-50, 51-60, 61-70 and over 70. The c 2 test was then performed on each age group versus the frequencies expected for males and females. In this case, the results indicate a highly significant difference (p < 0.01) for the males under 40, with a much higher percentage of G6PD-deficient subjects than expected (table 3): no difference was found between observed and expected frequencies in the other male age groups.

In females, the 51-60 group showed a significantly higher number (p < 0.02) of G6PD-deficient subjects (table 4): no differences were evidenced in the other groups.

 


Table 3. Distribution of G6PD deficiency in males with cholelighiasis in different age groups

 

Age G6PD ( + ) G6PD ( -- ) p ( c 2 )
n % n %
£ 40 12 75.00 4 25.00 0.01
41 - 50 22 84.02 4 15.38 n.s.
51-60 29 90.63 3 9.37 n.s.
61-70 24 92.31 2 7.69 n.s.
> 70 22 88.00 3 12.00 n.s.

The association between G6PD deficiency and cholelithiasis is statistically significant in males in the £ 40 age group (p < 0.01).

 


Table 4. Distribution of G6PD deficiency in females with cholelighiasis in different age groups

 

Age G6PD ( + ) G6PD ( -- ) p ( c 2 )
n % n %
£ 40 20 83.33 4 16.67 n.s.
41-50 37 82.22 8 17.78 n.s.
51-60 36 73.47 13 26.53 0.02
61-70 28 84.85 5 15.15 n.s.
> 70 19 82.61 4 17.39 n.s.

The association between G6PD deficiency and cholelithiasis is statistically significant in females in the 51-60 age group (p < 0.02).

 


Discussion
Cholelithiasis is more frequent, and has an earlier onset in subjects with chronic hemolytic anemia. According to Lawrie and Ham [6], the incidence of cholelithiasis in patients with hereditary spherocytosis is 60%, whereas Barker and Martin [7] reported an incidence of about 30%. Dewey et al. [8] found that 23% of patients with thalassemia major had cholelithiasis. By contrast, Borgna-Pignatti et al. [9] found only 3.6%, presumably because the latter patients had a better transfusion regimen. Sarnaik et al. [10] found that 63 out of 226 patients (27%) aged 2-18 years, with sickle cell disease had cholelithiasis. Zanella et al. [11] in a study of 25 subjects with chronic hemolytic anemia, due to pyruvate kinase deficiency, found gallstones in 5 cases (20%). Finally, cholelithiasis has been detected in 38% of subjects with chronic hemolytic anemia due to G6PD deficiency [1]. Our study demonstrates that G6PD-deficient subjects without chronic hemolytic anemia also develop cholelithiasis with a higher frequency than normal individuals. Statistical analysis showed significant differences for both male and female subjects.

The whole red cell population of G6PD-deficient male lacks enzymatic activity; since the erythrocytes have a shortened life span, there is a higher turnover of bilirubin than in normal subjects and, therefore, a higher probability of developing cholelithiasis. higher probability of developing cholelithiasis.

Heterozygous females have two different red cell populations: one with a normal enzyme activity and the other without (29 of our female patients had a 2dG6P utilization between 7.5% and 16%, 4 between 18.5 and 25% and the single homozygous female patient had a 2dG6P utilization of 33%). We can therefore assume that the percentage of G6PD-deficient creased erythrocyte turnover involves only a low percentage of cells, with a lower release of bilirubin and a proportionally lower increase in the prevalence of cholelithiasis than that found in G6PD-deficient males.

Grouping of patients by age showed that the highest percentage of G6PD-deficient subjects among males was found in the younger age group, whereas in females the 51-60 group contained the highest number of G6PD deficient patients.

According to our results, we might postulate that G6PD-deficient subjects have a greater tendency to develop cholelithiasis. No epidemiological data are however available to confirm this hypothesis to date; a study by our group on this aspect is already under way.

References

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Received: February 27, 1990
Accepted: September 17, 1990