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Background: Despite recent advances in the investigation of myeloproliferative neoplasms (MPN), the impact of genetic heterogeneity on its molecular pathogenesis has not been fully elucidated. Thus, in this study, we aim to characterize the genetic complexity in Korean patients with polycythemia vera (PV) and essential thrombocythemia (ET)., Methods: We conducted association studies using 84 single-nucleotide polymorphisms (SNPs) in 229 patients (96 with PV and 133 with ET) and 170 controls. Further, whole-genome sequencing was performed in six patients (two with JAK2 V617F and four with wild-type JAK2), and putative somatic mutations were validated in a further 69 ET patients. Clinical and laboratory characteristics were also analyzed., Results: Several germline SNPs and the 46 haplotype were significantly associated with PV and ET. Three somatic mutations in MPDZ, IQCH, and CALR genes were selected and validated. The frequency of the CALR mutation was 58.0% (40/69) in ET patients, who did not carry JAK2/MPL mutations. Moreover, compared with JAK2 V617F-positive patients, those with CALR mutations showed lower hemoglobin and hematocrit levels (P = 0.004 and P = 0.002, respectively), higher platelet counts (P =0.008), and a lower frequency of cytoreductive therapy (P = 0.014)., Conclusion: This study was the first comprehensive investigation of the genetic characteristics of Korean patients with PV and ET. We found that somatic mutations and the 46 haplotype contribute to PV and ET pathogenesis in Korean patients., (© 2016 Wiley Periodicals, Inc.)

Background: Intervertebral disc degeneration is now considered to be genetically determined in large part, with environmental factors also playing an important role. The human is known to uniquely exhibit variable numbers of tandem repeat polymorphism within the aggrecan CS1 domain. To date, the analysis of aggrecan's variable numbers of tandem repeat polymorphism has given inconsistent results with respect to the correlation between the allele's size and intervertebral disc degeneration. We wanted to investigate the patterns of the variable numbers of tandem repeat polymorphism in the aggrecan CS1 domain of Koreans, and we analyzed the association between the polymorphism and intervertebral disc degeneration., Method: A total of 66 males and 38 females participated in this study. Their ages ranged from 13 to 73 years. Genomic deoxyribonucleic acid was extracted from blood samples and PCR was carried out to detect the alleles of the aggrecan gene. The subjects were evaluated on MRI and they were classified by the number, severity, and morphology of disc degeneration., Findings: The genotyping identified 11 alleles ranging from 21 to 36 repeats. Alleles 13, 18, 19, and 20 were not found in this study. Of the 104 subjects, 29 (28%) were homozygotes and 75 (72%) were heterozygotes. Allele 27 (39%) was the most common form together with alleles 26 (26%) and 28 (14%). The allele 36 is the longest among the alleles ever discovered. For the case that the analysis was limited to subjects with the fourth decades or less, the 21 allele was significantly overrepresented among the persons with multilevel disc degeneration (p < 0.006)., Conclusions: Carrying a copy of the allele with 21 repeats might increase the risk of multiple disc degeneration in the subjects below the age of 40 years.

Non-syndromic familial thoracic aortic aneurysms and dissections (TAADs), inherited in an autosomal dominant manner in up to 19% of patients, are genetically heterogeneous. The ACTA2 gene, which encodes the vascular smooth muscle cell (SMC)-specific isoform of alpha-actin, is known to cause TAADs and occlusive vascular diseases, including coronary artery disease and premature ischemic stroke. We have investigated a Korean family with DeBakey type I aortic dissection related to pregnancy and a strong family history of TAADs. All affected family members underwent surgical repair of the ascending aorta. Other clinical features of familial TAAD, including inguinal hernias, iris flocculi, and livedo reticularis, were not observed. Histologic studies of aortic tissues showed medial degeneration and SMC hyperplasia in the aorta, consistent with previous observations. Molecular analyses of the ACTA2 gene showed a novel heterozygous missense mutation (c.76G>T; p.Asp26Tyr). Further analysis of a female patient and members of her family revealed that two affected sisters and her asymptomatic son had the same mutation. The novel Asp26Tyr mutation resides in SM alpha-actin subdomain 1 and is linked to TAAD with hypertrophy and disarray of SMCs and severe migraine, but not to livedo reticularis or iris flocculi. This study expands the spectrum of mutations of the ACTA2 gene by identifying a novel missense mutation. This is the first report of a pathologically- and genetically-confirmed family with TAAD in Korea.