Diagnosis status and genetic characteristics analysis of Fanconi anemia in China / 中华儿科杂志

Objective: To analyze the clinical and molecular diagnostic status of Fanconi anemia (FA) in China. Methods: The General situation, clinical manifestations and chromosome breakage test and genetic test results of 107 pediatric FA cases registered in the Chinese Blood and Marrow Transplantation Registry Group (CBMTRG) and the Chinese Children Blood and Marrow Transplantation Registry Group (CCBMTRG) from August 2009 to January 2022 were analyzed retrospectively. Children with FANCA gene variants were divided into mild and severe groups based on the type of variant, and Wilcoxon-test was used to compare the phenotypic differences between groups. Results: Of the 176 registered FA patients, 69 (39.2%) cases were excluded due to lack of definitive genetic diagnosis results, and the remaining 107 children from 15 hospitals were included in the study, including 70 males and 37 females. The age at transplantation treatment were 6 (4, 9) years. The enrolled children were involved in 10 pathogenic genes, including 89 cases of FANCA gene, 7 cases of FANCG gene, 3 cases of FANCB gene, 2 cases of FANCE gene and 1 case each of FANCC, FANCD1, FANCD2, FANCF, FANCJ, and FANCN gene. Compound heterozygous or homozygous of loss-of-function variants account for 69.2% (72/104). Loss-of-function variants account for 79.2% (141/178) in FANCA gene variants, and 20.8% (37/178) were large exon deletions. Fifty-five children (51.4%) had chromosome breakage test records, with a positive rate of 81.8% (45/55). There were 172 congenital malformations in 80 children.Café-au-Lait spots (16.3%, 28/172), thumb deformities (16.3%,28/172), polydactyly (13.9%, 24/172), and short stature (12.2%, 21/172) were the most common congenital malformations in Chinese children with FA. No significant difference was found in the number of congenital malformations between children with severe (50 cases) and mild FANCA variants (26 cases) (Z=-1.33, P=0.185). Conclusions: FANCA gene is the main pathogenic gene in children with FA, where the detection of its exon deletion should be strengthened clinically. There were no phenotypic differences among children with different types of FANCA variants. Chromosome break test is helpful to determine the pathogenicity of variants, but its accuracy needs to be improved.

Treatment of four cases of Fanconi anemia by allogeneic hematopoietic stem cell transplantation with low intensity conditional regimen / 中华血液学杂志

Objective: To evaluate the efficiency and safety of low intensity conditional regimen for children with Fanconi anemia (FA) receiving allogenic hematopoietic stem cells transplantation (allo-HSCT). Methods: Four patients diagnosed as Fanconi anemia were enrolled in this study. One patient received HLA-identical sibling donor hematopoietic stem cell transplantation, two patients underwent unrelated donor matched (UD) HSCT, and one patient received unrelated cord blood transplantation. The conditional regimen consisted of Busulfan with low dose of cyclophosphamide. Results: All 4 cases succeeded in allo-HSCT. The median time for neutrophils engraftment was 11(9-15) day, median time to platelets (PLT) engraftment was 12 (8-28) day. One case occurred with grade I of aGVHD, 1 case with hemorrhagic cystitis. No patient happened with hepatic veno-occlusive disease (VOD). Conclusion: Low intensity of conditional regimen is efficient and safe which should be recommended for FA patients with HSCT.