Publications by authors named "Vijay S Tonk"

Systematic evaluation of 80 history and 40 history findings diagnosed 1261 patients with Ehlers-Danlos syndrome (EDS) by direct or online interaction, and 60 key findings were selected for their relation to clinical mechanisms and/or management. Genomic testing results in 566 of these patients supported EDS relevance by their differences from those in 82 developmental disability patients and by their association with general rather than type-specific EDS findings. The 437 nuclear and 79 mitochondrial DNA changes included 71 impacting joint matrix (49 ), 39 bone (30 ), 22 vessel (12 , 43 vessel-heart (17/11/, 59 muscle (28 ), 56 neural (16 //), and 74 autonomic (13 /25porphyria related).

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Background: Mosaicism for chromosomal structural abnormalities, other than marker or ring chromosomes, is rarely inherited.

Methods: We performed cytogenetics studies and breakpoint analyses on a family with transmission of mosaicism for a derivative chromosome 8 (der(8)), resulting from an unbalanced translocation between the long arms of chromosomes 8 and 21 over three generations.

Results: The proband and his maternal half-sister had mosaicism for a der(8) cell line leading to trisomy of the distal 21q, and both had Down syndrome phenotypic features.

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Background: Our genomewide studies support targeted testing the most frequent genetic diseases by patient category: (1) pregnant patients, (2) at-risk conceptuses, (3) affected children, and (4) abnormal adults. This approach not only identifies most reported disease causing sequences accurately, but also minimizes incorrectly identified additional disease causing loci.

Methods: Diseases were grouped in descending order of occurrence from four data sets: (1) GeneTests 534 listed population prevalences, (2) 4129 high risk prenatal karyotypes, (3) 1265 affected patient microarrays, and (4) reanalysis of 25,452 asymptomatic patient results screened prenatally for 108 genetic diseases.

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In 5-10% of cases with CML, variant or complex translocations (CT) are seen that may result in atypical fluorescence in situ hybridization signal patterns. Dual color, dual fusion fluorescence in situ hybridization (D-FISH) patterns are instrumental in identifying the genesis of these CT, but their prognostic implications remain controversial. The most common mechanism is a two-step process in which a standard two-way translocation (9;22) is followed by subsequent rearrangements involving other chromosomes.

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Background: Congenital diaphragmatic hernia (CDH) is a life threatening birth defect. Most of the genetic factors that contribute to the development of CDH remain unidentified.

Objective: To identify genomic alterations that contribute to the development of diaphragmatic defects.

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Uterine leiomyomas are smooth muscle tumors most commonly seen in middle-aged women. Approximately 10% of these tumors contain rearrangements of the chromatin-remodeling gene HMGA2 at the chromosome band 12q14.3.

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Intestinal adenocarcinoma is a well-known complication of inflammatory bowel disease. Hematologic malignancies, most commonly lymphoma or acute myeloid leukemia, represent a much less well-recognized complication of these disorders; these typically occur in adults with ulcerative colitis. We report a fatal case of juvenile myelomonocytic leukemia associated with monosomy 7 in a young child with a clinical history of Crohn disease.

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Rapid fluorescence in situ hybridization (FISH) performed on 1,788 amniocenteses, using Aneuvision (Vysis) probes for chromosomes 13, 18, 21, X, and Y, over several years, yielded 115 cases with percentages of aneuploidy between 4 and 100%. All cases above 60% were confirmed to be positive by chromosome analysis. Fifteen of forty-one cases that would be considered inconclusive by generally accepted criteria (i.

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Chromosome deletions involving 1p36 are the most common known terminal rearrangements occurring at a frequency of approximately 1 in 5,000 live births. In contrast, duplications of the same region have been reported rarely. We describe a familial rearrangement der(1)del(1)(p36.

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Objective: To estimate the frequency of subtelomeric rearrangements in patients with sporadic and non-syndromic idiopathic mental retardation (IMR).

Methods: A total of 18 IMR patients were taken for the study. Selection criteria included no known syndromes or chromosomes abnormalities and known causes of IMR.

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Interstitial deletion of the proximal short arm of chromosome 4, extending from p14 to p16.1 region, results in a distinct clinical syndrome. This proximal 4p deletion syndrome is characterized by variable degrees of mental retardation, unusual facies and minor dysmorphic features.

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A five-year-old Caucasian male presented with developmental delay, minor dysmorphic features, and hyperactivity. Cytogenetic analysis showed the presence of a marker chromosome in the majority of cells analyzed. Fluorescence in situ hybridization (FISH) analyses using several alpha satellite probes, including D13Z1/D21Z1, did not reveal any signal on the marker chromosome.

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A 76-year-old male with a history of renal insufficiency was found to have anemia, an IgM kappa paraprotein on serum immunofixation studies, absence of lytic bone lesions, and findings in the bone marrow consistent with Waldenström macroglobulinemia (WM). Cytogenetic studies including fluorescence in situ hybridization (FISH) on the post-treatment bone marrow revealed the karyotype 46,XY,del(20)(q13.1q13.

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