Allogeneic stem cell transplantation for inherited metabolic disorders: 35 years' experience at a single institution.

Hematopoietic stem cell transplants for inherited metabolic disorders performed at Tokai University Hospital between June 5, 1986, and May 28, 2021, were analyzed and compared between the period before 2007 and the period from 2007 onward based on availability of medical resources. Transplants were performed for 38 patients with mucopolysaccharidosis, 33 with adrenoleukodystrophy, and 16 with another disorder. Before 2007, oral busulfan-based regimens were mainly used. From 2007 onward, intravenous busulfan-based regimens or 4 Gy of thoracoabdominal irradiation (TAI), fludarabine, and melphalan (Mel)/treosulfan were adopted. Between 2002 and 2010, adrenoleukodystrophy was treated with 12 Gy of TAI and Mel. HLA-identical sibling bone marrow was used in 43% of cases before 2007 and 15% from 2007 onward, while alternative donors were selected for other transplants. Overall survival and event-free survival (EFS) before 2007 and from 2007 onward were 76% and 62%, and 97% and 85%, respectively (P = 0.006 and 0.017). Transplant era predicted superior overall survival and EFS, while myeloablative conditioning also predicted EFS. The incidence of primary graft failure decreased from 2007 onward, especially in cord blood transplant when 4 Gy of TAI with 150 mg/m2 fludarabine and 180 mg/m2 Mel or 42 g/m2 treosulfan were used as conditioning.

Allogeneic Hematopoietic Cell Transplantation for Juvenile Myelomonocytic Leukemia with a Busulfan, Fludarabine, and Melphalan Regimen: JPLSG JMML-11.

Juvenile myelomonocytic leukemia (JMML), which is classified as a myelodysplastic/myeloproliferative neoplasm, is a rare hematologic malignancy of childhood. Most patients with JMML require allogeneic hematopoietic cell transplantation (HCT) as a curative therapy. A Japanese retrospective analysis demonstrated favorable outcomes for a busulfan (BU) + fludarabine (FLU) + melphalan (MEL) regimen, with an overall survival (OS) of 72% and an event-free survival (EFS) of 53%. To further validate the efficacy and safety of this regimen, the Japan Pediatric Leukemia/Lymphoma Study Group (JPLSG) conducted a nationwide prospective study, JMML-11. Between July 2011 and June 2017, 28 patients with newly diagnosed JMML were enrolled in JMML11. Low-dose chemotherapy for tumor control before HCT was recommended, and patients treated with AML-type chemotherapy and azacitidine were excluded. The conditioning regimen comprised i.v. BU, 16 doses administered every 6 h, with dose adjustment based on pharmacokinetic (PK) studies on days -11 to -8; FLU, 30 mg/m2/day or 1 mg/kg/day for patients <10 kg or age <1 year on days -7 to -4; and MEL, 90 mg/m2/day or 3 mg/kg/day for patients <10 kg or <1 year on days -3 to -2. The donor was selected by the physician in charge. A family donor was available for 7 patients (3 HLA-matched siblings, 3 HLA-1-antigen mismatched parents, and 1 haploidentical father). Overall, 21 patients received grafts from unrelated donors, including 8 HLA-matched donors and 13 HLA-mismatched donors. The graft source was related bone marrow (BM) for 7 patients, unrelated BM for 14 patients, and unrelated cord blood for 7 patients. Neutrophil engraftment was achieved in 21 of 28 patients (75%), with a median of 20.5 days (range, 11 to 39 days) after transplantation. The 3-year OS, 3-year EFS, 3-year relapse rate, and 3-year transplantation-related mortality were 63% (95% confidence interval [CI], 42% to 78%), 52% (95% CI, 32% to 69%), 18% (95% CI, 6% to 34%), and 21% (95% CI, 9% to 38%), respectively. WBC count before the conditioning regimen (≥7.0 × 109/L) was significantly associated with inferior EFS and OS. Body surface area ≥.5 m2, spleen size <4 cm before conditioning, and HLA-matched unrelated BM donors were significantly associated with better OS. Adverse effects related to the conditioning regimen included febrile neutropenia (86%), diarrhea (39%), hypoxemia (21%), and mucositis (18%). BU-associated toxicity, including sinusoidal obstruction syndrome (SOS) and thrombotic microangiopathy (TMA), occurred in 7 patients (25%; SOS, n = 6; TMA, n = 2). Retrospective analysis of PK data after the first BU dose in 23 patients, including 6 with SOS and 17 without SOS, did not show significant differences between groups. The JMML-11 study confirms the positive results of previous retrospective analyses. BU+FLU+MEL might become a standard conditioning regimen for patients with JMML.

RNF168 E3 ligase participates in ubiquitin signaling and recruitment of SLX4 during DNA crosslink repair.

SLX4/FANCP is a key Fanconi anemia (FA) protein and a DNA repair scaffold for incision around a DNA interstrand crosslink (ICL) by its partner XPF nuclease. The tandem UBZ4 ubiquitin-binding domains of SLX4 are critical for the recruitment of SLX4 to damage sites, likely by binding to K63-linked polyubiquitin chains. However, the identity of the ubiquitin E3 ligase that mediates SLX4 recruitment remains unknown. Using small interfering RNA (siRNA) screening with a GFP-tagged N-terminal half of SLX4 (termed SLX4-N), we identify the RNF168 E3 ligase as a critical factor for mitomycin C (MMC)-induced SLX4 foci formation. RNF168 and GFP-SLX4-N colocalize in MMC-induced ubiquitin foci. Accumulation of SLX4-N at psoralen-laser ICL tracks or of endogenous SLX4 at Digoxigenin-psoralen/UVA ICL is dependent on RNF168. Finally, we find that RNF168 is epistatic with SLX4 in promoting MMC tolerance. We conclude that RNF168 is a critical component of the signal transduction that recruits SLX4 to ICL damage.

Three Cases of Esophageal Cancer Related to Fanconi Anemia.

The risk of carcinogenesis increases after 20 years old in patients with Fanconi anemia (FA). We herein report three rare cases of FA combined with esophageal cancer in women; all patients were diagnosed with FA in early childhood. Patients 1 and 2 were diagnosed with advanced and superficial esophageal cancer, respectively, at 21 and 30 years old, respectively. Patient 3 was diagnosed with superficial esophageal cancer, underwent curative surgery at 26 years old, and survived for over 5 years without recurrence. Therefore, establishing a protocol for the early detection of esophageal cancer in FA patients over 20 years old is important.

Long-term outcome in patients with Fanconi anemia who received hematopoietic stem cell transplantation: a retrospective nationwide analysis.

We retrospectively analyzed nationwide records of 163 Fanconi anemia (FA) patients [aplastic anemia (AA), n = 118; myelodysplastic syndrome (MDS), n = 30; acute leukemia, n = 15] who underwent first allogeneic hematopoietic stem cell transplantation (HSCT) between 1987 and 2015 in Japan. An alternative donor was used in 119 (73%) patients, and 160 (98%) patients received a non-T-cell-depleted graft. With an 8.7-year median follow-up, 5-year overall survival (OS) was 81%. The 5-year OS was significantly higher in AA patients than in MDS and acute leukemia patients (89%, 71%, and 44%, respectively). In the MDS/leukemia group, factors associated with poor outcome in univariate analysis were older age at HSCT (≥ 18 years), conditioning regimen without anti-thymocyte or lymphocyte globulin, and grade II-IV acute graft-versus-host disease. After 1 year, of 137 survivors, 15 developed subsequent malignancies, of whom 12 were diagnosed with head and neck (HN)/esophageal cancer. An irradiation regimen and older age were associated with the risk of HN/esophageal cancer. Five of seven deaths were attributed to subsequent malignancies more than 5 years after HSCT. On the basis of the risk factors for HSCT in MDS/leukemia patients and subsequent malignancies, a more effective HSCT approach is required.

Two Aldehyde Clearance Systems Are Essential to Prevent Lethal Formaldehyde Accumulation in Mice and Humans.

Reactive aldehydes arise as by-products of metabolism and are normally cleared by multiple families of enzymes. We find that mice lacking two aldehyde detoxifying enzymes, mitochondrial ALDH2 and cytoplasmic ADH5, have greatly shortened lifespans and develop leukemia. Hematopoiesis is disrupted profoundly, with a reduction of hematopoietic stem cells and common lymphoid progenitors causing a severely depleted acquired immune system. We show that formaldehyde is a common substrate of ALDH2 and ADH5 and establish methods to quantify elevated blood formaldehyde and formaldehyde-DNA adducts in tissues. Bone-marrow-derived progenitors actively engage DNA repair but also imprint a formaldehyde-driven mutation signature similar to aging-associated human cancer mutation signatures. Furthermore, we identify analogous genetic defects in children causing a previously uncharacterized inherited bone marrow failure and pre-leukemic syndrome. Endogenous formaldehyde clearance alone is therefore critical for hematopoiesis and in limiting mutagenesis in somatic tissues.

Conditioning regimen for allogeneic bone marrow transplantation in children with acquired bone marrow failure: fludarabine/melphalan vs. fludarabine/cyclophosphamide.

Fludarabine/cyclophosphamide-based conditioning regimens are standard in bone marrow transplantation (BMT) for acquired bone marrow failure in children, however, graft failure may occur. Using the data from a nationwide transplantation registry, we compared the outcomes of children aged <16 years with acquired aplastic anemia and refractory cytopenia of childhood who underwent allogeneic BMT with either fludarabine/melphalan (n = 71) or fludarabine/cyclophosphamide (n = 296) between 2000 and 2016. The fludarabine/melphalan regimen provided excellent outcomes, with 3-year overall survival and failure-free survival rates of 98% and 97%, respectively. The 83% 3-year failure-free survival in the fludarabine/cyclophosphamide group was significantly inferior (P = 0.002), whereas the overall survival did not differ between the two groups. Late graft failure was the most common cause of treatment failure in the fludarabine/cyclophosphamide group, which experienced a significantly higher incidence of late graft failure than the fludarabine/melphalan group (11% vs. 3%; P = 0.035). Multivariate analyses showed that the fludarabine/melphalan regimen was associated with a better failure-free survival (hazard ratio [HR] 0.12; P = 0.005) and lower risk of late graft failure (HR 0.16; P = 0.037). Fludarabine/melphalan-based conditioning regimen can be a promising option for children with acquired bone marrow failure receiving BMT.

A founder variant in the South Asian population leads to a high prevalence of FANCL Fanconi anemia cases in India.

Fanconi anemia (FA) is a rare genetic disorder characterized by bone marrow failure, predisposition to cancer, and congenital abnormalities. FA is caused by pathogenic variants in any of 22 genes involved in the DNA repair pathway responsible for removing interstrand crosslinks. FANCL, an E3 ubiquitin ligase, is an integral component of the pathway, but patients affected by disease-causing FANCL variants are rare, with only nine cases reported worldwide. We report here a FANCL founder variant, anticipated to be synonymous, c.1092G>A;p.K364=, but demonstrated to induce aberrant splicing, c.1021_1092del;p.W341_K364del, that accounts for the onset of FA in 13 cases from South Asia, 12 from India and one from Pakistan. We comprehensively illustrate the pathogenic nature of the variant, provide evidence for a founder effect, and propose including this variant in genetic screening of suspected FA patients in India and Pakistan, as well as those with ancestry from these regions of South Asia.

Clinical Outcomes after Allogeneic Hematopoietic Stem Cell Transplantation in Children with Juvenile Myelomonocytic Leukemia: A Report from the Japan Society for Hematopoietic Cell Transplantation.

Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for juvenile myelomonocytic leukemia (JMML), but few large studies of HSCT for JMML exist. Using data from the Japan Society for Hematopoietic Cell Transplantation registry, we analyzed the outcomes of 129 children with JMML who underwent HSCT between 2000 and 2011. The 5-year overall survival (OS) rate and cumulative incidence of relapse were 64% and 34%, respectively. A regimen of busulfan/fludarabine/melphalan was the most commonly used (59 patients) and provided the best outcomes; the 5-year OS rate reached 73%, and the cumulative incidences of relapse and transplantation-related mortality were 26% and 9%, respectively. In contrast, the use of the irradiation-based myeloablative regimen was the most significant risk factor for OS (hazard ratio [HR], 2.92; P = .004) in the multivariate model. In addition, chronic graft-versus-host disease (GVHD) was strongly associated with lower relapse (HR, 0.37; P = .029) and favorable survival (HR, 0.22; P = .006). The current study has shown that a significant proportion of children with JMML can be cured with HSCT, especially those receiving the busulfan/fludarabine/melphalan regimen. Based on the lower relapse and better survival observed in patients with chronic GVHD, additional treatment strategies that focus on enhancing graft-versus-leukemia effects may further improve survival.

[Genetic analysis of Japanese patients with Fanconi anemia: novel findings].

Fanconi anemia (FA) is an inherited bone marrow failure syndrome characterized by multiple congenital abnormalities, progressive bone marrow failure, and a predisposition to malignancies, resulting from mutations in one of the 22 known FANC genes (from FANCA to FANCW). The proteins encoded by these genes participate in a deoxyribonucleic acid interstrand cross-link repair pathway, the so-called FA/BRCA pathway. The 22 FANC genes include hereditary breast and ovarian cancer susceptibility genes, such as BRCA1 or BRCA2. Patients with FA display a wide range of clinical phenotypes owing to the genetic heterogeneity of the disease; therefore, the molecular diagnosis is critical for the appropriate management of such patients. Recently, we successfully subtyped 97% of the 117 Japanese patients with FA and identified 215 mutant alleles through a comprehensive strategy. In this review, the characteristics of genetic subtyping and mutated FANC gene variants in Japanese patients with FA and the genotype-phenotype correlation in FA are summarized. In addition, the carrier frequency of pathogenic FANC genes and risk of cancer among the FANC gene mutation carriers in general Japanese population are discussed.

Pathogenic mutations identified by a multimodality approach in 117 Japanese Fanconi anemia patients.

Fanconi anemia is a rare recessive disease characterized by multiple congenital abnormalities, progressive bone marrow failure, and a predisposition to malignancies. It results from mutations in one of the 22 known FANC genes. The number of Japanese Fanconi anemia patients with a defined genetic diagnosis was relatively limited. In this study, we reveal the genetic subtyping and the characteristics of mutated FANC genes in Japan and clarify the genotype-phenotype correlations. We studied 117 Japanese patients and successfully subtyped 97% of the cases. FANCA and FANCG pathogenic variants accounted for the disease in 58% and 25% of Fanconi anemia patients, respectively. We identified one FANCA and two FANCG hot spot mutations, which are found at low percentages (0.04-0.1%) in the whole-genome reference panel of 3,554 Japanese individuals (Tohoku Medical Megabank). FANCB was the third most common complementation group and only one FANCC case was identified in our series. Based on the data from the Tohoku Medical Megabank, we estimate that approximately 2.6% of Japanese are carriers of disease-causing FANC gene variants, excluding missense mutations. This is the largest series of subtyped Japanese Fanconi anemia patients to date and the results will be useful for future clinical management.

Associations of complementation group, ALDH2 genotype, and clonal abnormalities with hematological outcome in Japanese patients with Fanconi anemia.

Fanconi anemia (FA) is a genetically and clinically heterogeneous disorder that predisposes patients to bone marrow failure (BMF), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). To study which genetic and phenotypic factors predict clinical outcomes for Japanese FA patients, we examined the FA genes, bone marrow karyotype, and aldehyde dehydrogenase-2 (ALDH2) genotype; variants of which are associated with accelerated progression of BMF in FA. In 88 patients, we found morphologic MDS/AML in 33 patients, including refractory cytopenia in 16, refractory anemia with excess blasts (RAEB) in 7, and AML in 10. The major mutated FA genes observed in this study were FANCA (n = 52) and FANCG (n = 23). The distribution of the ALDH2 variant alleles did not differ significantly between patients with mutations in FANCA and FANCG. However, patients with FANCG mutations had inferior BMF-free survival and received hematopoietic stem cell transplantation (HSCT) at a younger age than those with FANCA mutations. In FANCA, patients with the c.2546delC mutation (n = 24) related to poorer MDS/AML-free survival and a younger age at HSCT than those without this mutation. All patients with RAEB/AML had an abnormal karyotype and poorer prognosis after HSCT; specifically, the presence of a structurally complex karyotype with a monosomy (n = 6) was associated with dismal prognosis. In conclusion, the best practice for a clinician may be to integrate the morphological, cytogenetic, and genetic data to optimize HSCT timing in Japanese FA patients.

Common Variable Immunodeficiency Caused by FANC Mutations.

Common variable immunodeficiency (CVID) is the most common adult-onset primary antibody deficiency disease due to various causative genes. Several genes, which are known to be the cause of different diseases, have recently been reported as the cause of CVID in patients by performing whole exome sequencing (WES) analysis. Here, we found FANC gene mutations as a cause of adult-onset CVID in two patients. B cells were absent and CD4+ T cells were skewed toward CD45RO+ memory T cells. T-cell receptor excision circles (TRECs) and signal joint kappa-deleting recombination excision circles (sjKRECs) were undetectable in both patients. Both patients had no anemia, neutropenia, or thrombocytopenia. Using WES, we identified compound heterozygous mutations of FANCE in one patient and homozygous mutation of FANCA in another patient. The impaired function of FANC protein complex was confirmed by a monoubiquitination assay and by chromosome fragility test. We then performed several immunological evaluations including quantitative lymphocyte analysis and TRECs/sjKRECs analysis for 32 individuals with Fanconi anemia (FA). In total, 22 FA patients (68.8%) were found to have immunological abnormalities, suggesting that such immunological findings may be common in FA patients. These data indicate that FANC mutations are involved in impaired lymphogenesis probably by the accumulation of DNA replication stress, leading to CVID. It is important to diagnose FA because it drastically changes clinical management. We propose that FANC mutations can cause isolated immunodeficiency in addition to bone marrow failure and malignancy.

Clinical utility of next-generation sequencing for inherited bone marrow failure syndromes.

PURPOSE: Precise genetic diagnosis of inherited bone marrow failure syndromes (IBMFS), a heterogeneous group of genetic disorders, is challenging but essential for precise clinical decision making. METHODS: We analyzed 121 IBMFS patients using a targeted sequencing covering 184 associated genes and 250 IBMFS patients using whole-exome sequencing (WES). RESULTS: We achieved successful genetic diagnoses for 53 of 121 patients (44%) using targeted sequencing and for 68 of 250 patients (27%) using WES. In the majority of cases (targeted sequencing: 45/53, 85%; WES: 63/68, 93%), the detected variants were concordant with, and therefore supported, the clinical diagnoses. However, in the remaining 13 cases (8 patients by target sequencing and 5 patients by WES), the clinical diagnoses were incompatible with the detected variants. CONCLUSION: Our approach utilizing targeted sequencing and WES achieved satisfactory diagnostic rates and supported the efficacy of massive parallel sequencing as a diagnostic tool for IBMFS.Genet Med advance online publication 19 January 2017.

Successful acute lymphoblastic leukemia-type therapy in two children with mixed-phenotype acute leukemia.

Mixed-phenotype acute leukemia (MPAL) is a rare type of leukemia expressing both myeloid and lymphoid markers. There is limited information, especially on pediatric cases. Therefore, the optimal therapeutic approach to pediatric MPAL has not been defined. Here, we report two pediatric cases of MPAL. According to the 2008 World Health Organization (WHO) classification and European Group for the Immunological Characterization of Leukemias (EGIL) criteria, patient 1 was diagnosed with overt MPAL positive for the myeloid marker myeloperoxidase (MPO), and B-lymphoid markers. Patient 2 was diagnosed with T-cell acute lymphoblastic leukemia (T-ALL) using EGIL criteria. According to the 2008 WHO classification, however, patient 2 was diagnosed with overt MPAL positive for CD3, T-lymphoid markers and MPO. We chose an ALL-type therapy consisting of both lymphoid- and myeloid-directed agents; these patients have maintained complete remission following treatment. Further information on pediatric MPAL is needed to establish an appropriate therapeutic strategy including stem cell transplantation for this rare condition.

The phenotype and clinical course of Japanese Fanconi Anaemia infants is influenced by patient, but not maternal ALDH2 genotype.

Studies using Fanconi anaemia (FA) mutant mouse models suggested that the combination of a defective FA pathway and aldehyde dehydrogenase-2 (ALDH2) dysfunction could provoke bone marrow failure, leukaemia and developmental defects, and that both maternal and fetal aldehyde detoxification are crucial to protect the developing embryo from DNA damage. We studied the ALDH2 genotypes of 35 Japanese FA patients and their mothers. We found that a normal maternal ALDH2 allele was not essential for fetal development of ALDH2-deficient patients, and none of the post-natal clinical parameters were clearly affected by the maternal ALDH2 genotype in these patients.

High event-free survival rate with minimum-dose-anthracycline treatment in childhood acute promyelocytic leukaemia: a nationwide prospective study by the Japanese Paediatric Leukaemia/Lymphoma Study Group.

We evaluated the efficacy of treatment using reduced cumulative doses of anthracyclines in children with acute promyelocytic leukaemia (APL) in the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-P05 study. All patients received two and three subsequent courses of induction and consolidation chemotherapy respectively, consisting of all-trans retinoic acid (ATRA), cytarabine and anthracyclines, followed by maintenance therapy with ATRA. Notably, a single administration of anthracyclines was introduced in the second induction and all consolidation therapies to minimize total doses of anthracycline. The 3-year event-free (EFS) and overall survival rates for 43 eligible children were 83·6% [95% confidence interval (CI): 68·6-91·8%] and 90·7% (95% CI: 77·1-96·4%), respectively. Although two patients died of intracranial haemorrhage or infection during induction phases, no cardiac adverse events or treatment-related deaths were observed during subsequent phases. Patients not displaying M1 marrow after the first induction therapy, or those under 5 years of age at diagnosis, showed inferior outcomes (3-year EFS rate; 33·3% (95% CI: 19·3-67·6%) and 54·6% (95% CI: 22·9-78·0%), respectively). In conclusion, a single administration of anthracycline during each consolidation phase was sufficient for treating childhood APL. In younger children, however, conventional ATRA and chemotherapy may be insufficient so that alternative therapies should be considered.

[Diagnosis and management of inherited bone marrow failure syndrome].

The inherited bone marrow failure syndromes (IBMFS) are rare disorders in which there is usually some form of bone marrow failure and typical changes in physical appearance, associated with a family history of the same disorder. Patients with IBMFS have a very high risk of developing myelodysplastic syndrome, acute myeloid leukemia, and solid tumors. The latest technology applied to the molecular pathogenesis of these disorders has led to identification of specific genetic mutations and now facilitates determining the appropriate diagnosis and management of afflicted patients. In this section, we describe physical and laboratory findings and management of the major IBMFS: Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, and Diamond Blackfan anemia. We also discuss their possible implications in the clinical features of Japanese patients.

Clinical and genetic features of dyskeratosis congenita, cryptic dyskeratosis congenita, and Hoyeraal-Hreidarsson syndrome in Japan.

Dyskeratosis congenita (DKC) is an inherited bone marrow failure (BMF) syndrome typified by reticulated skin pigmentation, nail dystrophy, and mucosal leukoplakia. Hoyeraal-Hreidarsson syndrome (HHS) is considered to be a severe form of DKC. Unconventional forms of DKC, which develop slowly in adulthood but without the physical anomalies characteristic of DKC (cryptic DKC), have been reported. Clinical and genetic features of DKC have been investigated in Caucasian, Black, and Hispanic populations, but not in Asian populations. The present study aimed to determine the clinical and genetic features of DKC, HHS, and cryptic DKC among Japanese patients. We analyzed 16 patients diagnosed with DKC, three patients with HHS, and 15 patients with cryptic DKC. We found that platelet count was significantly more depressed than neutrophil count or hemoglobin value in DKC patients, and identified DKC patients with large deletions in the telomerase reverse transcriptase and cryptic DKC patients with RTEL1 mutations on both alleles. This led to some patients previously considered to have unclassifiable BMF being diagnosed with cDKC through identification of new gene mutations. It thus seems important from a clinical viewpoint to re-examine the clinical characteristics, frequency of genetic mutations, and treatment efficacy in DKC, HHS, and cDKC.