Context:The risk of thyroid cancer and multinodular goiter (MNG) in DICER1 syndrome, a rare tumor-predisposition disorder, is unknown.Objective:To quantify the risk of thyroid cancer and MNG in individuals with DICER1 syndrome.Design:Family-based cohort study.Setting:National Institutes of Health (NIH) Clinical Center (CC).Participants:The National Cancer Institute DICER1 syndrome cohort included 145 individuals with a DICER1 germline mutation and 135 family controls from 48 families.Interventions:Each individual completed a detailed medical history questionnaire. A subset underwent a 3-day evaluation at the NIH CC.Main Outcome Measures:The cumulative incidence of MNG (or thyroidectomy) was quantified using the complement of the Kaplan-Meier product limit estimator. We compared the observed number of thyroid cancers in the NCI DICER1 cohort with matched data from the Surveillance, Epidemiology, and End Results (SEER) Program. We performed germline and somatic (thyroid cancer, MNG) DICER1 sequencing.Results:By the age of 40 years, the cumulative incidence of MNG or thyroidectomy was 75% in women and 17% in men with DICER1 syndrome compared with 8% of control women (P < 0.001) and 0% of control men (P = 0.0096). During 3937 person-years of observation, individuals with DICER1 syndrome had a 16-fold increased risk of thyroid cancer (95% confidence interval, 4.3 to 41; P < 0.05) compared with the SEER rates. Of 19 MNG nodules and 3 thyroid cancers, 16 (84%) and 3 (100%), respectively, harbored germline and somatic pathogenic DICER1 mutations.Conclusions:We propose a model of thyroid carcinogenesis in DICER1 syndrome. Early-onset, familial, or male MNG should prompt consideration of the presence of DICER1 syndrome.

Background Germline mutations in DICER1 increase the risk of various tumors, including pleuropulmonary blastoma. Macrocephaly and symmetric overgrowth has been reported in some, but not all, patients with mosaic DICER1 RNase IIIb mutations; the prevalence of these features in individuals with constitutional germline DICER1 mutations is unknown. Methods We analyzed prospectively collected auxology data from 67 DICER1 mutation carriers and 43 family controls. We assessed differences between groups using an exact test for proportions and generalized estimating equations for continuous dependent variables. Results Twenty-eight DICER1 mutation carriers (42%) were macrocephalic, and none had an occipital-frontal circumference (OFC) below the 3rd centile, which significantly differed from family controls, of whom five were macrocephalic (12%) and two had OFC below the 3rd centile (5%) (P<0.001). DICER1 mutation carriers were taller than familial controls after controlling for gender (P=0.048), but similar proportions of both groups were above the 97th centile of population norms. Head circumference remained increased after adjusting for differences in height. Conclusions For the first time, we establish macrocephaly as a common finding in the DICER1 syndrome. Like some of the other tumor-predisposition disorders, macrocephaly may be a useful, albeit a subtle, clinical clue to the DICER1 syndrome diagnosis.

The objective was to investigate the regulatory effect of polyunsaturated fatty acids (PUFAs) on mRNA expression of key genes involved in homocysteine (Hcy) metabolism. Eighty male Sprague Dawley rats were randomly divided into eight groups. The oils were orally administered daily for 8 weeks. Plasma Hcy, phospholipids fatty acids, and mRNA expression were determined. Compared with the control group, plasma Hcy was significantly decreased in the 22:6n-3 and conjugated linoleic acid (CLA) groups; mRNA expression of Mthfr was significantly upregulated in the 22:6n-3, 20:5n-3, and 18:3n-3 groups and downregulated in the 18:2n-6 and stearolic acid (SO) groups. Mat1a was upregulated in the 22:6n-3, 20:5n-3, 18:3n-3, and CLA groups. In addition, Cbs was upregulated in the 22:6n-3, 20:5n-3, 18:3n-3 and CLA groups while downregulated in 18:2n-6 and SO groups. Dietary 22:6n-3 and CLA decrease the plasma concentration of Hcy. mRNA expression of Mthfr, Mat1a, Cbs and Pemt, Gnmt, Mtrr, and Bad is upregulated by n-3 PUFA and downregulated by n-6 PUFA. CLA upregulates mRNA expression of Mat1a and Cbs.

Background Neurofibromatosis type 1 (NF1) is a common, autosomal dominant tumor-predisposition disorder that arises secondary to mutations in the tumor suppressor gene NF1. Cephalometry is an inexpensive, readily available and non-invasive technique that is under-utilized in studying the NF1 craniofacial phenotype. An analysis of NF1 cephalometry was first published by Heervä et al. in 2011. We expand here on that first investigation with a larger cohort of adult and pediatric patients affected with NF1 and sought objective insight into the NF1 facies, said to feature hypertelorism and a broad nasal base, from cephalometric analysis. Methods We obtained cephalograms from 101 patients with NF1 (78 adults and 23 children) from two NF1 protocols at the National Institutes of Health. Each subject had an age-, gender- and ethnicity-matched control. We used Dolphin software to make the cephalometric measurements. We assessed the normality of differences between paired samples using the Shapiro-Wilk test and evaluated the significance of mean differences using paired t-tests and adjusted for multiple testing. We explored the relationship between the cephalometric measurements and height, head circumference and interpupillary distance. Results In this dataset of American whites with NF1, we confirmed in a modestly larger sample many of the findings found by Heerva et al. in an NF1 Finnish cohort. We found a shorter maxilla, mandible, cranial base, (especially anteriorly, p = 0.0001) and diminished facial height in adults, but not children, with NF1. Only one adult exhibited hypertelorism. Conclusions The cephalometric differences in adults arise in part from cranial base shortening and thus result in a shorter face, mid-face hypoplasia, reduced facial projection, smaller jaw, and increased braincase globularity. In addition, we suggest that NF1 sphenoid bone shortening, a common event, is consistent with an intrinsic NF1 bone cell defect, which renders the bone more vulnerable to a random “second hit” in NF1, leading to sphenoid wing dysplasia, a rare event.

Children with biallelic mutations in FANCD1/BRCA2 are at uniquely high risks of leukemia and solid tumors. Preemptive bone marrow transplantation (PE-BMT) has been proposed to avoid the development of leukemia, but empirical study of PE-BMT is unlikely due to the rarity of these children and unknown benefit of PE-BMT. We used survival analysis to estimate the risks of leukemia, and the expected survival if leukemia could be eliminated by curative PE-BMT. We used the results in a decision analysis model to explore the plausibility of PE-BMT for children with variable ages at diagnosis and risks of transplant-related mortality. For example, PE-BMT at one year of age with a 10% risk of transplant-related mortality increased the mean survival by 1.7 years. The greatest benefit was for patients diagnosed between one and three years of age, after which the benefit of PE-BMT decreased with age at diagnosis, and the risk of death from solid tumors constituted a relatively greater burden of mortality. Our methods may be used to model survival for other hematologic disorders with limited empirical data and a pressing need for clinical guidance.

Our report is the first to systematically characterize renal function and anatomy in a large prospective cohort of DICER1-carriers and DICER1-negative family controls. DICER1-carriers may be at increased risk of structural anomalies of the kidney or collecting system. The role for DICER1 in renal morphogenesis merits additional investigation.

Background: Fanconi anemia (FA) is a primarily autosomal recessive bone marrow failure and cancer predisposition syndrome associated with mutations in the FA/BRCA DNA damage response pathway. The median age at diagnosis of FA is 7 years; the diagnosis is often made due to recognition of characteristic birth defects. Over half of patients with FA develop severe bone marrow failure (BMF) by age 50 years, one in ten develop acute myeloid leukemia (AML), and one in four develop a solid tumor (ST) as their first event. Successful allogeneic bone marrow transplantation (BMT) is potentially curative of FA's hematologic manifestations but introduces risks of transplant-related mortality (TRM) and morbidity. We hypothesized that preemptive bone marrow transplantation (PE-BMT) for individuals diagnosed prior to the development of BMF, AML, or ST, would increase event-free survival (EFS) if the risks associated with transplantation were sufficiently low. Methods: We developed a mathematical decision model (Markov) of EFS with the assumption that successful PE-BMT would eliminate the risks of BMF and AML, but would introduce a procedural risk of TRM. We modeled the EFS of PE-BMT at variable ages at decision ranging from birth to 30 years, and without and with an increase in the rate of ST following BMT above the level in untransplanted patients with FA. We developed our model using empirical estimates of the age-specific conditional probabilities of BMF, AML, and ST (Alter et al, BJH, 2010), and a 4.4-fold estimated increased risk of ST following BMT (Rosenberg et al, Blood, 2005). We tested the sensitivity of the model over a range of values for TRM and an increased risk of ST following BMT, and evaluated the model using TreeAge Pro 2014 (TreeAge Software, Inc, Williamstown MA, http://www.treeage.com). Results: Children diagnosed at age 7 years receiving standard care could expect to live an additional 16 years before experiencing BMF, ST, or AML, and thus survive free of an event until an average age of 23 years. If those children instead received PE-BMT with a 10% risk of TRM, they could expect to survive an additional 29 years and be cancer-free until an average age of 36 years. However, if PE-BMT were to increase the rate of ST 4.4-fold, PE-BMT would only increase the mean EFS by 2 years over standard care, until an average age of 25 years. PE-BMT would increase the mean EFS at all ages if TRM was ≤10% and the risk of ST was the same as in untransplanted patients. PE-BMT would decrease the mean EFS when performed after age 9 years if there was 10% TRM and a 4.4-fold increased rate of ST. PE-BMT at age 18 years with 10% TRM would increase the mean EFS if it did not affect the trajectory to ST, but would decrease the mean EFS if it modestly increased the rate of ST (≥2.2-fold). Conclusions: PE-BMT in patients with FA may provide an event-free survival benefit so long as the risk of TRM appears to be low (≤10%) and the regimen has little or no impact on the development of ST. The decision was particularly sensitive to the increase in ST following BMT. Our model suggests that older ages at decision, higher risks of TRM, and greater relative risks of ST following transplant would lead to PE-BMT being a less desirable strategy. Our estimates of event-free survival may be used to inform shared decision making between providers and families, with attention paid to patient values and the morbidity associated with BMT. Disclosures No relevant conflicts of interest to declare.

Fanconi anemia (FA) is a rare inherited bone marrow failure syndrome associated with high risks of severe bone marrow failure (BMF), acute myeloid leukemia (AML), and solid tumors (ST). Bone marrow transplantation (BMT) provides a theoretical cure for hematologic risks (BMF, AML), but it introduces uncertain risks of transplantation-related mortality (TRM) and carcinogenicity. We developed a mathematical (Markov) decision model to estimate event-free survival (EFS) conditional on age based on per-year cause-specific hazard rates. We assumed that preemptive (PE) BMT eliminates the risks of BMF and AML, but it may introduce independent risks of TRM or influence the trajectory to ST. Our model suggested that the expected mean EFS in FA is higher for PE-BMT at young ages, with minimal risk of TRM and with little carcinogenicity. PE-BMT in adults decreased expected EFS because of the greater competing risk of ST in adulthood. Estimates of EFS conditioned on attained age may be used in shared decision-making when clinicians must counsel patients using limited data. Our methods may be used to model early transplantation in other blood disorders for which hematopoietic stem cell transplantation mitigates some but not all of the risks.