儿童遗传性骨髓衰竭综合征诊断方法探讨

目的探讨遗传性骨髓衰竭综合征(IBMFS)的诊断方法。方法对6例IBMFS患儿的临床表现、体征、血常规、骨髓形态学、染色体核型分析、染色体断裂、骨髓造血干细胞培养、胰腺外分泌功能、内分泌激素检测、尿筛查、叶酸、维生素B12定量、血红蛋白F、细胞免疫/体液免疫、骨骼X线检查,以及其中4例行特定基因扩增及测序进行分析。结果 6例患儿均以一系或二系病态造血为突出特点,伴持续高胎儿血红蛋白血症起病,均表现生长迟滞、矮小,骨骼异常、皮肤、黏膜改变亦较为突出,部分病例合并内分泌疾病、神经系统异常。4例克隆出IBMFS的关键致病基因。结论完整的病史、详尽的体格检查可以为IBMFS的临床诊断提供重要线索。特定的基因检测有助于早期诊断。     

遗传性骨髓衰竭综合征的研究进展

遗传性骨髓衰竭综合征是一组先天性疾病.其发病机制尚不完全明确,目前已发现部分致病基因,而且初步掌握了其诊断和治疗方法.此类疾病的诊断多依据典型的临床表现及相关实验室检查.随着基因检测的开展,致病基因检测正成为确诊该类疾病的主要方法.目前造血干细胞移植是唯一可能治愈本疾病的方法,支持和对症治疗在延缓和改善病情方面至关重要,基因治疗尚不成熟,其他治疗手段均在不断探索中.     

Pregnancy outcomes in mothers of offspring with inherited bone marrow failure syndromes

1 Background

Children with inherited bone marrow failure syndromes (IBMFSs) may be symptomatic in utero, resulting in maternal and fetal problems during the pregnancy. Subsequent pregnancies by their mothers should be considered “high risk”.

2 Methods

We retrospectively analyzed outcomes of 575 pregnancies in 165 unaffected mothers of offspring with Fanconi anemia (FA), dyskeratosis congenita (DC), Diamond–Blackfan anemia (DBA), and Shwachman–Diamond syndrome (SDS) for events noted during pregnancy, labor, and delivery. We compared outcomes of pregnancies with affected and unaffected offspring within each group of mothers and with the general population.

3 Results

The rates of miscarriage (12–20%), elective abortion (5–10%), and live birth (68–78%) among mothers of all IBMFS groups were similar and comparable with general population rates but recurrent miscarriages (≥2) were significantly more common in mothers of offspring with DBA and SDS. Offspring with FA were more frequently born small for gestational age (SGA) than unaffected babies (39% vs. 4%) and had fetal malformations (46%) with 18% having three or more, often necessitating early delivery and surgery; offspring with DC had higher rates of SGA (39% vs. 8%) and fetal distress (26% vs. 3%); and offspring with DBA had fetal hypoxia (19% vs. 1%) leading to preterm and emergency cesarean deliveries (26% vs. 6%). Offspring with early‐onset severe phenotypes had the most prenatal and peripartum adverse events.

4 Conclusion

We identified the high‐risk nature of pregnancies in mothers with IBMFS‐affected fetuses, suggesting the need for prepregnancy counseling and monitoring of subsequent pregnancies by high‐risk fetal–maternal specialists.     

Monosomy 7/del (7q) in inherited bone marrow failure syndromes: A systematic review

Inherited bone marrow failure syndromes (IBMFS) are rare cancer predisposition syndromes with an especially high risk of transformation to myelodysplastic syndrome (MDS) and/or acute myeloid leukemia (AML). We performed a retrospective systematic review of reported MDS/AML arising in the eight most common IBMFS to determine the frequency and outcome of chromosome 7 abnormalities. We identified 738 MDS/AML cases of 4,293 individuals. Monosomy 7 or del (7q) occurred in ～17%. Greater understanding of the roles played by sequential acquisition of genetic and cytogenetic changes will provide insights into myeloid leukemogenesis and improve the surveillance and hopefully outcomes for individuals with IBMFS.     

Disease progression in recently diagnosed patients with inherited marrow failure syndromes: a Canadian Inherited Marrow Failure Registry (CIMFR) report

BACKGROUND: Inherited bone marrow failure syndromes (IMFSs) are genetic disorders characterized by defective single-lineage or multi-lineage hematopoiesis. IMFS patients are at risk for severe cytopenias, development of marrow cytogenetic abnormalities (MCA), myelodysplasia (MDS), and malignancy. The rate of disease progression and proportion of patients at risk for these complications is currently unclear. We examined recently diagnosed IMFS patients to determine distribution of diagnoses, disease progression and development of significant outcomes. METHODS: The CIMFR is a prospective multi-center study established in 2001 to register all IMFS patients in Canada. Analysis was restricted to patients diagnosed after November 30, 1997. Summary statistics were used to depict the study population while survival was described using the Kaplan-Meier method. RESULTS: 74 CIMFR patients were considered recently diagnosed. Median age at diagnosis was 2.7 years (range, birth to 40.6). Annual follow-up data were available for 53 (72%) patients. The five most prevalent diagnoses were Fanconi anemia (FA), Shwachman-Diamond syndrome (SDS), Diamond-Blackfan anemia (DBA), dyskeratosis congenita (DKC), and Kostmann's neutropenia (KS). Eighteen (24%) patients were unclassifiable. Twenty-eight (53%) follow-up patients had disease progression as indicated by new or worsening cytopenias, new marrow changes, or initiation of transfusion support and/or medical therapy. Fourteen (19%) fulfilled minimal diagnostic criteria for myelodysplasia. Eleven patients had hematopoietic stem cell transplantation (HSCT) by first follow-up. Five patients have died. Survival at 36 months is 89.8 +/- 5.7%. CONCLUSIONS: IMFS patients are often diagnosed at a young age. The relative distribution of diagnoses is similar to previous reviews of published cases; however, 25% of patients are currently unclassifiable. Disease progression has occurred in approximately 50% of follow-up patients. Early mortality is noted. Continued prospective observation of these patients is warranted.     

Bone marrow transplant for a girl with bone marrow failure and cerebral palsy

Bone marrow transplantation (BMT) has been used with increasing frequency to treat congenital bone marrow failure syndrome (CBMFs) successfully. Decision to perform BMT, however, is difficult in the case of comorbidity because of regimen‐related toxicities. We describe here a child with CBMFs, severe cerebral palsy (CP) at Gross Motor Function Classification System level V and mental retardation (MR) who was transfusion dependent despite various medications. She underwent BMT from an HLA‐1 locus‐mismatched unrelated donor. Although engraftment was successful, no neurological improvement was seen 5 years after BMT. While CBMFs patients who have CP and MR could undergo transplantation safely, they may not benefit neurologically from BMT.     

Low serum lipids suggest severe bone marrow failure in children with aplastic anemia

BACKGROUND: Significantly low serum lipid levels are occasionally seen at the time of diagnosis in children with aplastic anemia (AA). The aim of the present study was to clarify the pathologic and clinical significance of pretreatment serum lipid levels in AA. METHODS: A questionnaire seeking precise data about AA in pediatric patients, including the initial laboratory data at the time of onset of AA and the clinical course of these patients, was sent to 18 institutes in Japan; 13 institutes responded to the questionnaire. In this retrospective study, data concerning hematologic examination and serum lipids were available for analysis in 127 children with AA. Serum lipoprotein patterns were analyzed using conventional agarose electrophoresis in eight patients. In order to elucidate the cause of hypolipidemia in AA, we assayed serum macrophage colony stimulating factor (M-CSF), which is well known to have apparent cholesterol-lowering activity, by using an enzyme-linked immunosorbent assay in seven patients with hypocholesterolemia and compared the results with those obtained in patients with iron-deficiency anemia (IDA). RESULTS: We found that pretreatment total cholesterol (TC) and triglyceride levels in the serum correlated well with counts of both nucleated cells and hemopoietic cells in the bone marrow (BM) and were inversely correlated with the lymphocyte ratio in both the BM and peripheral blood. Patients with serum TC lower than 150 mg/dL showed a poor response to any form of therapy except BM transplantation. There was no difference in the serum lipoprotein patterns between the controls and patients examined. The serum M-CSF level was significantly higher in patients with TC levels lower than 150 mg/dL compared with controls. CONCLUSIONS: These results indicate that the pretreatment serum lipid level may reflect hematopoietic activity within the BM and can help to predict the therapeutic response of each case of AA to treatment with immunosuppressive drugs, corticosteroids and anabolic steroids. These results also indicate that M-CSF may be one of the contributing causes of the hypocholesterolemia that occurs in both AA and IDA.     

Current diagnosis of inherited bone marrow failure syndromes

Prompt and accurate diagnosis is required for optimal treatment and genetic counseling of patients with inherited bone marrow failure syndromes (IBMFS). However, the diverse clinical picture of these syndromes and their rareness is often associated with diagnostic difficulties. Recently, an improved diagnostic approach is possible by the cloning of many of the causative genes. Fanconi anemia (FA) patients belong to at least 12 complementation groups, of which 11 genes have been cloned. An approach combining an induced chromosomal breakage test, detection of FANCD2-L by Western blot analysis, complementation group analysis, and detailed mutation analysis enables unraveling the causative mutation in the majority of patients. With the use of such strategies, genotype/phenotype correlations in FA are evolving. In dyskeratosis congenita mutations in DCK1, TERC, and TERT genes have been identified, but mutations have been found in less than half of these patients. In patients with Shwachman-Diamond syndrome, mutations in the SBDS gene were found in approximately 90% of patients. In Diamond-Blackfan anemia the RSP19 gene is mutated in 20-25% of patients. Heterozygote ELA2 mutations are found in 60-80% of severe congenital neutropenia patients. All patients with congenital amegakaryocytic thrombocytopenia have mutations in the thrombopoietin receptor gene c-Mpl.     

Bone marrow failure syndromes in children

There are several common themes that are emerging from our expanding knowledge about the inherited bone marrow failure syndromes. Patients have a spectrum of birth defects, which are relatively characteristic for each syndrome. but overlap in features such as poor growth. radial ray anomalies, and involvement of skin, eyes, renal, cardiac, skeletal, and other organs. Within each syndrome the composition and severity of the physical phenotype varies widely, and it may require the astute observer to make the correct diagnoses in the milder cases. There is also a wide spectrum to the hematologic picture. These range from single cytopenias such as DBA, SCN, and TAR, which do not develop pancytopenia, to SD and Amega patients who begin with deficiency of a specific single lineage, but evolve to aplastic anemia, to patients with FA or DC, who may present with a deficiency of any one of the cell lines, but almost inevitably end up with full-blown aplastic anemia. Acute myeloid leukemia has been observed in FA, DBA, DC, SD, SCN, and Amega, although not yet in TAR patients. MDS has also been reported in all of the same disorders as AML, although whether it is a preleukemic condition or an independent bone marrow dyspoiesis is not yet clear. Solid tumors are also now appearing in patients whose underlying disease involves hematopoiesis and physical development. These tumors occur at much younger ages than in the general population, in patients who do not appear to have the usual risk factors, and have patterns that are characteristic to the syndrome, such as head and neck and gynecologic cancers in FA and DC, and osteogenic sarcomas in DBA. The other syndromes have not yet been reported to have a propensity for solid tumors. Several genes have been identified that are mutant in some of the syndromes, although the pathophysiology is still not entirely clear. The inheritance patterns include X-linked recessive, autosomal dominant, autosomal recessive, and even mitochondrial. The FA gene products appear to cooperate, and are important in the pathways involved in response to DNA damage. However, the role of this pathway in developmental defects, hematopoietic failure, and the specific malignancies in FA is not fully elucidated. The DC gene products are important for maintenance of telomere length, which may have relevance to development of aplastic anemia and malignancies, but the relation to the physical phenotype is less apparent. The role of mutations in c-mpl in Amega is more straightforward. since the gene codes for the receptor for thrombopoietin. which is the hormone required for megakaryocyte and platelet development; patients with mutant c-mpl do not have birth defects. The role of mutations in RPS19 in erythropoiesis or developmental defects in DBA patients is not obvious, and the increased frequency of osteogenic sarcomas suggests that at least that subset of patients may have a mutant tumor suppressor gene (such as p53, the mutant gene in Li-Fraumeni syndrome) [68]. Although patients with SCN have mutations in neutrophil elastase, patients with similar mutations may have relatively benign cyclic neutropenia, or may even have normal neutrophil levels [69,70]. The mitochondrial gene deletions in Pearson's Syndrome result in variable degrees of acidosis, and varied organ involvement due to heteroplasmy. Thus, the disorders included under the rubric "inherited bone marrow failure syndromes" have clinical. hematologic, oncologic, and genetic diversity.     

Granulocyte-colony-stimulating factor after allogeneic and autologous bone marrow transplantation in children

We evaluated the use of granulocyte CSF (G-CSF) after both allogeneic BMT (allo-BMT) and autologous BMT (ABMT) in children. After allo-BMT, G-CSF was used in 15 children who were compared with 20 historical controls. The ABMT patients were two sequential groups: the G-CSF group of 13 children and 11 historical controls. The patients were conditioned with different high-dose chemotherapy regimens with or without total body irradiation. G-CSF was administered at 5 μg/kg/day s.c. and was continued until an absolute neutrophil count (ANC) of 1,000 × 10⁶/l was reached. Following allo-BMT, G-CSF accelerated myeloid engraftment with a difference of 5 days at the ANC level of 500 × 10⁶/l (P < 0.02) and 9 days at 1,000 × 10⁶/l (P < 0.001). In the ABMT patients, G-CSF also accelerated myeloid engraftment. The difference between the G-CSF group and the control group was 6 days at ANC 200 (P < 0.05), 11 days at ANC 500 (P < 0.02), and 17 days at ANC 1,000 (P < 0.005). In the ABMT patients, benefit by G-CSF was also observed in a smaller number of days with fever and days on antibiotics. We conclude that G-CSG significantly accelerated myeloid engraftment, after both allogeneic and autologous BMT in children, and also decreased the duration of febrile illness in the ABMT patients. © 1996 Wiley-Liss, Inc.     

Autologous bone marrow transplantation in children with acute lymphoblastic leukemia

We report 25 children with acute lymphoblastic leukemia (ALL) treated with purged autologous bone marrow transplantation (ABMT) at a single center. Two children with high-risk ALL were transplanted in first remission and 23 with relapsing ALL were transplanted in second (n = 21) or third (n = 2) remission. There was no procedure-related mortality. The median time to engraftment (i.e. to reach a polymorphonuclear cell count of 0.5 x 10(9)/l) was 25 days (range 16-45 days). Seven children relapsed, four within five months after ABMT: 18 of 25 children (72%) are in continuous complete remission after a median follow-up period of 50 months (range 5-71 months). The predicted long-term disease-free survival is 65% in the whole group and 61% in those transplanted after relapse. Relapse-free children returned to normal activities within three months after ABMT. The major side effects were development of cataract and gonadal insufficiency. We consider the results promising, but our data do not allow comparison with results reported from treatment with chemotherapy alone, since some of our patients were referred from other centers and represent a selected patient group. Long-term follow-up of well-defined patient populations is necessary to evaluate the effect of ABMT.     

More aggressive bone marrow screening in retinoblastoma patients is not indicated: the memorial Sloan-Kettering cancer center experience

BACKGROUND: Bone marrow involvement in retinoblastoma patients is rare in the more industrialized nations. The purpose of the current study was to determine the frequency of bone marrow involvement in our series of retinoblastoma patients and to investigate whether the use of four bone marrow aspirates (BMA) and two bone marrow biopsies (BMB) has greater sensitivity for the detection of metastatic disease compared to what has been previously reported. METHODS: Retrospective analysis of the charts of 54 patients with retinoblastoma was performed. We performed 265 BMA, 134 BMB (4 aspirates and 2 biopsies per evaluation), and 67 lumbar punctures (LPs) in 54 patients with retinoblastoma. RESULTS: There were no patients found with bone marrow or cerebrospinal fluid (CSF) involvement at the time of the initial diagnosis. Although no patient died of distant metastases, two patients developed metastatic disease at recurrence, involving the bone marrow and other sites. For these two patients all four aspirates and two biopsies were positive for disease at the time of recurrence. CONCLUSIONS: Despite the use of four BMA and two BMB (as opposed to one bone marrow aspirate that is routinely performed in other centers), the detection of patients with metastatic disease was similar to what has been previously reported. Based on these data more aggressive evaluation of the bone marrow in retinoblastoma patients with clinically limited disease using four aspirates and two biopsies cannot be supported.     

Single institution experience with high-dose cyclophosphamide,continuous infusion vincristine,escalating doses of VP-16-213, and total body irradiation with unpurged bone marrow rescue in children with neuroblastoma

Seven consecutive autologous bone marrow transplants were performed in children with neuroblastoma with very good partial remission (VGPR). A combination of cyclophosphamide, escalating doses of VP-16-213, continuous infusion vincristine, and total body irradiation followed by infusion with unpurged bone marrow was used. The dose-limiting toxicity in this regimen was mucositis which occurred when the total dose of VP-16-213 was 2,400 mg/m². The response rate to this regimen was 4/7 (-CR 48+, 21+, 21+, 35+ mo) 3/7 had a CR/PR post transplant with progressive disease between 1 and 4 months later (mean 2.6 mo). We conclude that this regimen is well tolerated when the maximum dose of VP-16-213 does not exceed 1,800 mg/m². Further evaluation will be necessary with this regimen to determine its therapeutic value in a larger number of patients with neuroblastoma.