Variant ALDH2 is associated with accelerated progression of bone marrow failure in Japanese Fanconi anemia patients

Abstract

Fanconi anemia (FA) is a severe hereditary disorder with defective DNA damage response and repair. It is characterized by phenotypes including progressive bone marrow failure (BMF), developmental abnormalities, and increased occurrence of leukemia and cancer. Recent studies in mice have suggested that the FA proteins might counteract aldehyde-induced genotoxicity in hematopoietic stem cells. Nearly half of the Japanese population carries a dominant-negative allele (rs671) of the aldehyde-catalyzing enzyme ALDH2 (acetaldehyde dehydrogenase 2), providing an opportunity to test this hypothesis in humans. We examined 64 Japanese FA patients, and found that the ALDH2 variant is associated with accelerated progression of BMF, while birth weight or the number of physical abnormalities was not affected. Moreover, malformations at some specific anatomic locations were observed more frequently in ALDH2-deficient patients. Our current data indicate that the level of ALDH2 activity impacts pathogenesis in FA, suggesting the possibility of a novel therapeutic approach.

Figure 1

Effects of the ALDH2 deficiency on Japanese FA patients. (A-B) Cumulative incidence of BMF (A) or MDS/AML (B) were analyzed in 64 FA subjects. Numbers of AA, GA, and GG patients were 3, 25, and 36, respectively. (C) Cumulative incidence of BMF was analyzed in patients with confirmed biallelic FANCA mutations having protein truncations and/or large deletions (n = 12). Numbers of AA, GA, and GG patients were 1, 5, and 6, respectively. P values shown were calculated by the Gray test. In panel A, P values between genotypes were 8.625 × 10⁻⁷ (GG vs GA), 2.107 × 10⁻¹⁰ (GG vs AA), 1.259 × 10⁻⁶ (GA vs AA), respectively. In (B), the difference between GG and GA subjects was not significant (P = .4564479), whereas other statistical comparisons were highly significant (GG vs AA, 2.911 × 10⁻¹⁰; GA vs AA, 8.813 × 10⁻⁸). In panel C, the P values between GG and GA, GG and AA, or GA and AA were calculated as 0.001228433, 0.01430588, 0.02534732, respectively. (D) Percentage of birth weight or (E) total number of physical abnormalities (shown in supplemental Table 1) in 64 FA patients with 3 ALDH2 genotypes. Birth weight was normalized to mean weight at gestational age in Japan. Mean and SEM are indicated. Birth weight records were missing for 3 patients (supplemental Table 1). There was no significant difference between the ALDH2 genotypes (Kruskal-Wallis test). (F) Frequency (percentage) of cardiovascular, radial, thumb, skeletal, kidney, and extensive malformations in each ALDH2 genotype. P values were calculated by the Cochran-Armitage test for trend, which detects statistical significance of effects across the genotypes. The error bars represent 95% confidence intervals.