Robin Mueller

Stem Cell Collection and Gene Transfer in Fanconi Anemia

Fanconi anemia (FA) is a rare genetic syndrome characterized by progressive bone marrow failure (BMF), congenital anomalies, and a predisposition to malignancy. Successful gene transfer into hematopoietic stem cells (HSCs) could reverse BMF in this disease. We developed clinical trials to determine whether a sufficient number of CD34+ stem cells could be collected for gene modification and to evaluate the safety and efficacy of HSC-corrective gene transfer in FA genotype A (FANCA) patients. Here, we report that FA patients have significant depletion of their BM CD34+ cell compartment even before severe pancytopenia is present. However, oncoretroviral-mediated ex vivo gene transfer was efficient in clinical scale in FA-A cells, leading to reversal of the cellular phenotype in a significant percentage of CD34+ cells. Re-infusion of gene-corrected products in two patients was safe and well tolerated and accompanied by transient improvements in hemoglobin and platelet counts. Gene correction was transient, likely owing to the low dose of gene-corrected cells infused. Our early experience shows that stem cell collection is well tolerated in FA patients and suggests that collection be considered as early as possible in patients who are potential candidates for future gene transfer trials.

Numerical chromosomal changes and risk of development of myelodysplastic syndrome–acute myeloid leukemia in patients with Fanconi anemia

Fanconi Anemia (FA) is an inherited bone marrow failure syndrome characterized by congenital abnormalities, progressive marrow failure and predisposition to myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and solid tumors. The most common acquired chromosomal aberrations in FA patients are trisomy of 1q and monosomy of chromosome 7; the latter is known to be associated with poor prognosis. A few reports also suggest that gains of 3q are associated with progression to MDS-AML and overall poor prognosis. It is not uncommon for patients with Fanconi anemia to have easily detectable (oligoclonal) chromosomal alterations in their still normal (nonmalignant) marrow, which makes it even more challenging to determine the import of such alterations. We conducted a retrospective longitudinal analysis of fluorescent in situ hybridization (FISH) analysis for gains in 1q and 3q and for monosomy 7 and 7q deletions on 212 bone marrow samples from 77 children with FA treated at our institution between 1987 and 2007. Given the baseline increased chromosomal instability and defective DNA repair in patients with FA, which leads to unbalanced chromosomal aberrations such as deletions, insertions, and translocations, for the purpose of this analysis an abnormal clone was defined as ≥10% abnormal cells. Chromosome 3 and 7 aberrations were associated with increased risk of developing MDS-AML (P = 0.019 and P < 0.001 respectively), although the significance of chromosome 3 aberrations disappeared when different observation times were accounted for. Gain of 1q alone did not predict development of MDS-AML. In conclusion, children with FA should be followed closely with FISH analyses, because some of the clonal chromosomal abnormalities may be early indicators of progression toward MDS-AML and thus also of the need for hematopoietic stem cell transplantation.

The clinical phenotype of children with Fanconi anemia caused by biallelic FANCD1/BRCA2 mutations

Fanconi anemia (FA) is characterized by progressive marrow failure, congenital anomalies, and predisposition to malignancy. Biallelic FANCD1/BRCA2 mutations are the genetic basis of disease in a small proportion of children with FA with earlier onset and increased incidence of leukemia and solid tumors. Patients with FA have increased sensitivity to chemotherapy and radiation, and upon development of a solid tumor, require modification of these therapies. We report clinical and molecular features of three patients with FA associated with FANCD1/BRCA2 mutations, including two novel mutations, and discuss treatment of malignancy and associated side effects in this particularly vulnerable group. Pediatr Blood Cancer 2012; 58: 462–465.

Impaired immune function in children with Fanconi anaemia

Fanconi anaemia is an autosomal recessive or X‐linked disease characterized by progressive bone marrow failure, variable congenital abnormalities and a predisposition to malignancy. Reports of immune function in this population are limited, and include only specific areas of immune performance, showing variable defects. We report a cross‐sectional immunological assessment in 10 children with FA. Absolute numbers of B cells and natural killer (NK) cells were reduced compared to controls (P = 0·048 and P = 0·0002, respectively), while absolute number of T cells were within normal range. Perforin and granzyme content of NK cells was reduced (P < 0·00001 and P = 0·0057, respectively) along with the NK cell cytotoxicity (P < 0·001). Antigen proliferation in response to tetanus was decreased (P = 0·008) while responses to candida and phytohaemagglutinin were not. Cytotoxic T cell function was also reduced (P < 0·0001). Immunoglobulin G levels were normal in those evaluated. Our series represents the first attempt at a comprehensive quantitative and functional evaluation of immune function in this rare group of patients and demonstrates a significant deficit in the NK cell compartment, a novel quantitative B cell defect, along with abnormal cytotoxic function. These findings may be especially relevant in this patient population with known predisposition to DNA damage and malignancy.

Endocrine phenotype of children and adults with Fanconi anemia

Features of Fanconi anemia (FA) are well known, including bone marrow failure, congenital anomalies such as radial anomalies, renal and ear anomalies, tracheo‐esophageal fistula, imperforate anus, and elevated risk for cancer. We sought to further characterize the endocrine phenotype in children and adults with FA.

Abnormalities in glucose tolerance are common in children with fanconi anemia and associated with impaired insulin secretion

To determine prevalence of abnormal glucose metabolism in Fanconi Anemia (FA).

Improved growth velocity during thyroid hormone therapy in children with Fanconi anemia and borderline thyroid function.

Children with Fanconi anemia (FA) tend to have short stature, mild thyrotropin (TSH) elevation, and borderline low free thyroxine (FT4). Objective was to examine whether thyroid hormone therapy improves linear growth in children with FA and borderline thyroid function tests

Oral Human Papillomavirus Is Common in Individuals with Fanconi Anemia

Background: Fanconi anemia is a rare genetic disorder resulting in a loss of function of the Fanconi anemia–related DNA repair pathway. Individuals with Fanconi anemia are predisposed to some cancers, including oropharyngeal and gynecologic cancers, with known associations with human papillomavirus (HPV) in the general population. As individuals with Fanconi anemia respond poorly to chemotherapy and radiation, prevention of cancer is critical. Methods: To determine whether individuals with Fanconi anemia are particularly susceptible to oral HPV infection, we analyzed survey-based risk factor data and tested DNA isolated from oral rinses from 126 individuals with Fanconi anemia and 162 unaffected first-degree family members for 37 HPV types. Results: Fourteen individuals (11.1%) with Fanconi anemia tested positive, significantly more (P = 0.003) than family members (2.5%). While HPV prevalence was even higher for sexually active individuals with Fanconi anemia (17.7% vs. 2.4% in family; P = 0.003), HPV positivity also tended to be higher in the sexually inactive (8.7% in Fanconi anemia vs. 2.9% in siblings). Indeed, having Fanconi anemia increased HPV positivity 4.9-fold (95% CI, 1.6–15.4) considering age and sexual experience, but did not differ by other potential risk factors. Conclusion: Our studies suggest that oral HPV is more common in individuals with Fanconi anemia. It will be essential to continue to explore associations between risk factors and immune dysfunction on HPV incidence and persistence over time. Impact: HPV vaccination should be emphasized in those with Fanconi anemia as a first step to prevent oropharyngeal cancers, although additional studies are needed to determine whether the level of protection it offers in this population is adequate. Cancer Epidemiol Biomarkers Prev; 24(5); 864–72. ©2015 AACR.

Etanercept treatment in Fanconi anaemia; combined US and Italian experience

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Bone mineral density is normal in children with Fanconi anemia

Conflicting data exist regarding whether low bone mineral density (BMD) is associated with Fanconi anemia (FA). The current study identified the frequency of low BMD in FA, expecting low BMD even in childhood and before HCT.