Douglas R. Stewart

Clinical characteristics of patients in studies of left ventricular dysfunction (SOLVD).

The Studies of Left Ventricular Dysfunction (SOLVD) trials were designed to evaluate the effects of enalapril on long-term mortality in patients with severe left ventricular (LV) dysfunction. Patients with LV ejection fractions less than or equal to 0.35 and symptoms of congestive heart failure (CHF) were enrolled in the treatment trial, whereas those with no history of overt CHF and taking no treatment directed for LV dysfunction were enrolled in the prevention trial. The baseline clinical characteristics of SOLVD patients were compared to characterize differences between patients in these 2 separate but concurrent trials. From over 70,000 patients screened with LV dysfunction, 4,228 patients were enrolled in the prevention trial and 2,569 patients in the treatment trial. Ischemic heart disease was the primary cause of LV dysfunction in both prevention (83%) and treatment (71%) trial patients. Prior myocardial infarction was present in 80% of the prevention and 66% of the treatment trial patients (p less than 0.001). In the prevention trial, infarction was recent (less than or equal to 6 months) in 27% patients and remote (greater than 6 months) in 57% patients. Treatment trial patients had proportionately more women (20 vs 13%; p less than 0.001) and non-Caucasians (20 vs 14%; p less than 0.001), as well as the coexisting risk factors of hypertension (42 vs 37%; p less than 0.001) and diabetes (26 vs 15%; p less than 0.001) than did prevention trial patients. Clinical characteristics of patients in both trials were influenced by the gender and race of enrolled patients. Similarly, coronary artery bypass surgery was performed less often in women and non-Caucasians.(ABSTRACT TRUNCATED AT 250 WORDS)

Family-Based Analysis of Candidate Genes for Polycystic Ovary Syndrome

CONTEXT Polycystic ovary syndrome (PCOS) is a complex disorder having both genetic and environmental components. A number of association studies based on candidate genes have reported significant association, but few have been replicated. D19S884, a polymorphic marker in fibrillin 3 (FBN3), is one of the few association findings that has been replicated in independent sets of families. OBJECTIVE The aims of the study are: 1) to genotype single nucleotide polymorphisms (SNPs) in the region of D19S884; and 2) to follow up with an independent data set, published results reporting evidence for PCOS candidate gene associations. DESIGN The transmission disequilibrium test (TDT) was used to analyze linkage and association between PCOS and SNPs in candidate genes previously reported by us and by others as significantly associated with PCOS. SETTING The study was conducted at academic medical centers. PATIENTS OR OTHER PARTICIPANTS A total of 453 families having a proband with PCOS participated in the study. Sisters with PCOS were also included. There was a total of 502 probands and sisters with PCOS. INTERVENTION(S) There were no interventions. MAIN OUTCOME MEASURE(S) The outcome measure was transmission frequency of SNP alleles. RESULTS We identified a six-SNP haplotype block spanning a 6.7-kb region on chromosome 19p13.2 that includes D19S884. SNP haplotype allele-C alone and in combination with D19S884-allele 8 is significantly associated with PCOS: haplotype-C TDT chi(2) = 10.0 (P = 0.0016) and haplotype-C/A8 TDT chi(2) = 7.6 (P = 0.006). SNPs in four of the other 26 putative candidate genes that were tested using the TDT were nominally significant (ACVR2A, POMC, FEM1B, and SGTA). One SNP in POMC (rs12473543, chi(2) = 9.1; P(corrected) = 0.042) is significant after correction for multiple testing. CONCLUSIONS A polymorphic variant, D19S884, in FBN3 is associated with risk of PCOS. POMC is also a candidate gene of interest.

The chromosome 9q subtelomere deletion syndrome.

The chromosome 9q subtelomere deletion syndrome (9qSTDS) is among the first and most common clinically recognizable syndromes to arise from widespread testing by fluorescent in situ hybridization (FISH) of subtelomere deletions. There are about 50 reported cases worldwide. Affected individuals invariably have severe hypotonia with speech and gross motor delay. The facial gestalt is distinct and features absolute or relative micro‐ or brachycephaly, hypertelorism, synophrys, and/or arched eyebrows, mid‐face hypoplasia, a short nose with upturned nares, a protruding tongue with everted lower lip and down‐turned corners of the mouth. Approximately half of affected individuals have congenital heart defects (primarily ASD or VSD). A significant minority have epilepsy and/or behavioral and sleep disturbances. A variety of other major and minor eye, ear, genital, and limb anomalies have been reported. Most patients have sub‐microscopic deletions of the subtelomere region of chromosome 9q34.3 that range from <400 kb to >3 Mb. The 9qSTDS is caused by haplo‐insufficiency of EHMT1, a gene whose protein product (Eu‐HMTase1) is a histone H3 Lys 9 (H3‐K9) methyltransferase. This was established by identification of three patients with features of the syndrome and either mutations or a balanced translocation in EHMT1. H3‐K9 histone methylation is restricted to the euchromatin of mammals and functions to silence individual genes. Deletion size does not correlate with the severity of the 9qSTDS since patients with mutations in EHMT1 are as severely affected as those with submicroscopic deletions. Patients clinically suspected of having the 9qSTDS but with normal subtelomere deletion testing by FISH or MLPA should be considered for detailed 9q MLPA analysis and/or sequencing of EHMT1. EHMT1 is another example in the growing list of genes responsible for brain development that appear to play a role in chromatin remodeling. Published 2007 Wiley‐Liss, Inc.

Pleuropulmonary Blastoma: A Report on 350 Central Pathology–Confirmed Pleuropulmonary Blastoma Cases by the International Pleuropulmonary Blastoma Registry

Pleuropulmonary blastoma (PPB) has 3 subtypes on a tumor progression pathway ranging from type I (cystic) to type II (cystic/solid) and type III (completely solid). A germline mutation in DICER1 is the genetic cause in the majority of PPB cases.

Mitotic recombination as evidence of alternative pathogenesis of gastrointestinal stromal tumours in neurofibromatosis type 1

Background: Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder resulting in the growth of a variety of tumours, and is inherited in an autosomal dominant pattern. Gastrointestinal stromal tumours (GISTs) are mesenchymal tumours that commonly harbour oncogenic mutations in KIT or PDGFRA and are thought to arise from the interstitial cells of Cajal (ICC; the pacemaker cells of the gut). Aim: To characterise two patients with NF1 and GISTs. Methods: Two patients were genotyped for germline mutations in NF1. GISTs from both patients were genotyped for somatic mutations in KIT and PDGFRA. Loss of heterozygosity (LOH) of NF1 in one GIST was assessed by genotyping seven microsatellite markers spanning 2.39 Mb of the NF1 locus in the tumour and in genomic DNA. The known germline mutation in NF1 was confirmed in GIST DNA by sequencing. The copy number of the mutated NF1 allele was determined by multiplex ligand-dependent probe amplification. Results: GISTs from both patients were of wild type for mutations in KIT and PDGFRA. In the GIST with adequate DNA, all seven markers were informative and showed LOH at the NF1 locus; sequencing of NF1 from that GIST showed no wild-type sequence, suggesting that it was lost in the tumour. Multiplex ligand-dependent probe amplification analysis showed that two copies of all NF1 exons were present. Conclusions: This is the first evidence of mitotic recombination resulting in a reduction to homozygosity of a germline NF1 mutation in an NF1-associated GIST. We hypothesise that the LOH of NF1 and lack of KIT and PDGFRA mutations are evidence of an alternative pathogenesis in NF1-associated GISTs.

FTO and MC4R gene variants are associated with obesity in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility in women. It is also associated with metabolic disturbances that place women at increased risk for obesity and type 2 diabetes. There is strong evidence for familial clustering of PCOS and a genetic predisposition. However, the gene(s) responsible for the PCOS phenotypes have not been elucidated. This two-phase family-based and case-control genetic study was designed to address the question of whether SNPs identified as susceptibility loci for obesity in genome-wide association studies (GWAS) are also associated with PCOS and elevated BMI. Members of 439 families having at least one offspring with PCOS were genotyped for 15 SNPs previously shown to be associated with obesity. Linkage and association with PCOS was assessed using the transmission/disequilibrium test (TDT). These SNPs were also analyzed in an independent case-control study involving 395 women with PCOS and 176 healthy women with regular menstrual cycles. Only one of these 15 SNPs (rs2815752 in NEGR1) was found to have a nominally significant association with PCOS (χ2 = 6.11, P = 0.013), but this association failed to replicate in the case-control study. While not associated with PCOS itself, five SNPs in FTO and two in MC4R were associated with BMI as assessed with a quantitative-TDT analysis, several of which replicated association with BMI in the case-control cohort. These findings demonstrate that certain SNPs associated with obesity contribute to elevated BMI in PCOS, but do not appear to play a major role in PCOS per se. These findings support the notion that PCOS phenotypes are a consequence of an oligogenic/polygenic mechanism.

Human skeletal myosin heavy chain genes are tightly linked in the order embryonic-IIa-IId/x-IIb-perinatal-extraocular

Myosin heavy chain (MyHC) is the major contractile protein of muscle. We report the first complete cosmid cloning and definitive physical map of the tandemly linked human skeletal MyHC genes at 17p13.1. The map provides new information on the order, size, and relative spacing of the genes, and it resolves uncertainties about the two fastest twitch isoforms. The physical order of the genes is demonstrated to contrast with the temporal order of their developmental expression. Furthermore, nucleotide sequence comparisons allow an approximation of the relative timing of five ancestral duplications that created distinct genes for the six isoforms. A firm foundation is provided for molecular analysis in patients with suspected primary skeletal myosinopathies and for detailed modelling of the hypervariable surface loops which dictate myosins kinetic properties.

DICER1-pleuropulmonary blastoma familial tumor predisposition syndrome: A unique constellation of neoplastic conditions

Abstract Germline mutations in DICER1 are associated with increased risk for a wide variety of neoplastic conditions, including pleuropulmonary blastoma, cystic nephroma, nasal chondromesenchymal hamartoma, ovarian Sertoli-Leydig cell tumors, botryoid embryonal rhabdomyosarcoma of the uterine cervix, ciliary body medulloepithelioma, pineoblastoma, pituitary blastoma, and nodular thyroid hyperplasia or thyroid carcinoma. These tumors may be seen in isolation or in constellation with other characteristic tumor types in individuals or family members. Here we describe the medical history of a child with a heterozygous, loss-of-function germline DICER1 mutation and multiple tumors associated with the syndrome. Although germline mutations in DICER1 are rare, tumors of these types will be seen by practicing pathologists and should prompt consideration of an underlying DICER1 mutation.

Diagnosis, management, and complications of glomus tumours of the digits in neurofibromatosis type 1

Background Glomus tumours are benign painful tumours of the glomus body, a thermoregulatory shunt in the digits. Glomus tumours of the fingers and toes are associated with the monogenic disorder neurofibromatosis type 1 (NF1) and are recently recognised as part of the NF1 phenotype. Methods and Results A multi-institutional experience with 15 individuals with NF1 and glomus tumours of the fingers or toes is reported. The majority of individuals presented with at least two of the symptoms in the classic triad of localised tenderness, severe paroxysmal pain, and sensitivity to cold. Appearance of the nail and finger or toe is often normal. Women are affected more often than men. Multifocal tumours are common. There is often a delay in diagnosis of many years and clinical suspicion is key to diagnosis, although magnetic resonance imaging may be useful in some scenarios. Surgical extirpation can be curative; however, local tumour recurrence and metachronous tumours are common. Three of our patients developed signs and symptoms of the complex regional pain syndrome. Conclusions Glomus tumours in NF1 are more common than previously recognised and NF1 patients should be specifically queried about fingertip or toe pain.

Quantification of thyroid cancer and multinodular goiter risk in the DICER1 syndrome: a family-based cohort study.

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.