• Title/Summary/Keyword: fragile X mental retardation

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Prenatal Population Screening for Fragile X Carrier and the Prevalence of Premutation Carriers in, Korea

  • Han, Sung-Hee;Heo, Yun-Ah;Yang, Young-Ho;Kim, Young-Jin;Cho, Han-Ik;Lee, Kyoung-Ryul
    • Journal of Genetic Medicine
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    • v.9 no.2
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    • pp.73-77
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    • 2012
  • Purpose: Fragile X carrier detection before or at early pregnancy through a wide screening program may not only confer a risk of having offspring with Fragile X syndrome (FXS), but may also confer a risk for Fragile X-associated primary ovarian insufficiency and Fragile X-associated tremor/ataxia syndrome. However, prior to the implementation of such a program, the carrier prevalence in a population and the availability of effective screening test should be evaluated. The aim of our study was to determine the prevalence of premutation carriers and to evaluate the feasibility of screening test. Materials and Methods: The blood samples were obtained from 8,641 pregnant women with no family history of mental retardation. We performed a three-primer CGG repeat primed (RP) PCR using the AmplideX$^{TM}$ FMR1 PCR kit (Asuragen, Inc. Austin, TX, USA). Samples showing full mutation alleles were reflexed to Southern blot analysis for methylation status and sizing. Results: Among the 8,641 women, we found 8 premutation carriers (1:1,090, 0.09%) and 46 women with an intermediate allele (1:190, 0.53%). No woman was found to carry the fully mutated allele. All the detected alleles were within the CGG repeat range of 8-117. Among the 8,641 samples, 29 and 30 CGG repeats represent 66.6% of all cases. The CGG RP PCR method provides robust detection of expanded alleles and resolves allele zygosity, thus minimizing the number of samples that require Southern blot analysis. Conclusion: This is the first study that has focused on the prevalence of FXS premutation carriers and FMR1 allele distribution in normal pregnant women. These data have important implications for population-based fragile X carrier screening in Korea.

Neuronal function and dysfunction of CYFIP2: from actin dynamics to early infantile epileptic encephalopathy

  • Zhang, Yinhua;Lee, Yeunkum;Han, Kihoon
    • BMB Reports
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    • v.52 no.5
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    • pp.304-311
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    • 2019
  • The cytoplasmic FMR1-interacting protein family (CYFIP1 and CYFIP2) are evolutionarily conserved proteins originally identified as binding partners of the fragile X mental retardation protein (FMRP), a messenger RNA (mRNA)-binding protein whose loss causes the fragile X syndrome. Moreover, CYFIP is a key component of the heteropentameric WAVE regulatory complex (WRC), a critical regulator of neuronal actin dynamics. Therefore, CYFIP may play key roles in regulating both mRNA translation and actin polymerization, which are critically involved in proper neuronal development and function. Nevertheless, compared to CYFIP1, neuronal function and dysfunction of CYFIP2 remain largely unknown, possibly due to the relatively less well established association between CYFIP2 and brain disorders. Despite high amino acid sequence homology between CYFIP1 and CYFIP2, several in vitro and animal model studies have suggested that CYFIP2 has some unique neuronal functions distinct from those of CYFIP1. Furthermore, recent whole-exome sequencing studies identified de novo hot spot variants of CYFIP2 in patients with early infantile epileptic encephalopathy (EIEE), clearly implicating CYFIP2 dysfunction in neurological disorders. In this review, we highlight these recent investigations into the neuronal function and dysfunction of CYFIP2, and also discuss several key questions remaining about this intriguing neuronal protein.

Chicken FMRP Translational Regulator 1 (FMR1) Promotes Early Avian Influenza Virus Transcription without Affecting Viral Progeny Production in DF1 Cells

  • Woo, Seung Je;Park, Young Hyun;Han, Jae Yong
    • Korean Journal of Poultry Science
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    • v.48 no.2
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    • pp.81-90
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    • 2021
  • Avian influenza viruses (AIVs) must utilize host cellular factors to complete their life cycle, and fragile X mental retardation protein (FMRP) has been reported to be a host factor promoting AIV ribonucleoprotein (vRNP) assembly and exports vRNP from the nucleus to the cytoplasm. The functional role of chicken FMRP translational regulator 1 (cFMR1) as a host factor of AIV is, however, poorly understood. In this study, we targeted the cFMR1 gene in DF1 cells using clustered regularly interspaced short palindromic repeats/Cas9-mediated genome editing to examine the functional role of cFMR1 as a host factor of AIV. We found that cFMR1 stimulated viral gene transcription during early stages of the viruses' life cycle and did not affect viral progeny production and viral polymerase activity in DF1 cells 24 hours post infection. cFMR1 overexpression did not exert significant effects on virus production, compared to the control. Therefore, unlike in mammalian systems (e.g., humans or mice), cFMR1 did not play a pivotal role in AIV but only seemed to stimulate viral proliferation during early stages of the viral life cycle. These results imply that the interplay between host factors and AIV differs between mammals and avian species, and such differences should be considered when developing anti-viral drugs for birds or establishing AIV-resistant bird models.

Cytogenetic Study and Clinical Features in Patients with Klinefelter's Syndrome and Y Chromosomal Abnormalities (Klinefelter 증후군 및 Y염색체 이상으로 진단된 환자들의 염색체 결과 및 임상 양상)

  • Moon, Shin-Yong;Choi, Seok-Tae;Ko, Hee-Jung;Oh, Sun-Kyung;Han, Jung-Ho;Suh, Chang-Suk;Kim, Seok-Hyun;Choi, Young-Min;Kim, Jung-Gu;Lee, Jin-Yong
    • Clinical and Experimental Reproductive Medicine
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    • v.26 no.1
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    • pp.43-54
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    • 1999
  • Klinefelter's syndrome is a very important disease in gynecologic endocrinologic fields, because the patients with this karyotype complain of infertility, azospermia and ambiguous genitalia. Y chromosome is an important chromosome which determine genetic sex and the structure of gonad and genitalia. In this study, to elucidate the cytogenetic characteristics and clinical features of Klinefelter's syndrome and Y chromosomal abnormalities in Korea, we studied 303 cases of Klinefelter's syndrome and 11 cases of Y chromosomal abnormalities which were diagnosed by chromosomal analysis at the Cytogenetic Laboratory, Institute of Reproductive Medicine and Population, Seoul National University for 12 years from January 1984 to December 1996. The results of this study showed as follows: 1. In a total of 9275 cases, there were 303 cases (3.3%) of Klinefelter's syndromes, 11 cases (0.1%) of Y chromosomal abnormalities. 2. In 102 cases of patients showed typical clinical features of Klinefelter's syndrome, 101 cases (99%) of them were diagnosed to Klinefelter's syndrome in karyotyping. 3. In 303 cases of Klinefelter's syndrome, there were 277 cases (91.4%) of 47,XXY complement, 16 cases (5.3%) of mosaicism, 2 cases (0.7%) of 48,XXXY, 5 cases (1.7%) of 48,XXYY and 3 cases (1.0%) of 49,XXXXY. 4. In 303 cases of Klinefelter's syndrome, 284 cases (93.7%) of them were diagnosed after puberty and only 19 cases (6.3%) of them were diagnosed before puberty. 5. In 303 cases of Klinefelter's syndrome, there were 146 cases (48.2%) of patients with infertility-associated chief complaints, 101 cases (33.3%) of patients with typical clinical features of Klinefelter's syndrome, 22 cases (7.3%) of patients with ambiguous genitalia. 6. In patients with Klinefelter's syndrome, 48,XXYY and 49,XXXXY had serious symptoms such as mental retardation, developmental delay, Down syndrome-like features, congenital anomalies, but 48,XXYY and other mosaicisms had infertility-associated symptoms or ambiguous genitalia. 7. The 8 cases of polysomy Y (XYY complement) showed several serious symptoms such as Down syndrome-like features, mental retardation, fragile X syndrome-like feature, congenital anomalies, ambiguous genitalia which could be detected before puberty.

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Assessment of Chromosomal Analyses of 1,180 Cases Suspected of Chromosomal Aberrations (염색체이상을 의심한 1,180례의 염색체 분석 결과 검토)

  • Jeong, Hyeon Kyoung;Ahn, Eun Young;Rim, Sung Soo;Kim, Eun Young;Kim, Kyoung Sim;Kim, Yong Wook;Kim, Ki Bok
    • Clinical and Experimental Pediatrics
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    • v.45 no.3
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    • pp.311-319
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    • 2002
  • Purpose : We have performed this study to obtain reference data for the distribution of chromosomal aberrations in Korea. Methods : We analyzed 1,180 chromosomal study cases from Kwang ju Christian Hospital during the past 25 years. 756 cases suspected of characteristic chromosomal aberration syndromes and 424 cases with hermaphroditism, mild sexual abnormalities, multiple anomalies, or mental & growth retardation were included. Results : The male to female ratio of autosomal aberration syndromes was 1.2 : 1. 78.6% of autosomal aberrations were diagnosed under 1 year of age, whereas 89.8% of sex chromosomal aberrations were diagnosed over 12 years of age. Among 1,180 cases, 612 ones had chromosomal aberrations(51.9%) : 590 of 756 cases suspected of chromosomal aberration syndromes had aberrations( 78.0%), whereas 22 of 424 showing the above other features had aberrations(5.2%). Autosomal aberrations appeared in 514 cases(83.8%) and sex chromosomal aberrations appeared in 98 cases(16.2%). The most frequently observed abberation in autosomal aberrations was Down syndrome, followed by E, D, B, A and C group aberrations. The most common abberation in sex chromosomal aberrations was Turner syndrome, followed by Klinefelter syndrome and Fragile X syndrome. Conclusion : It is of vital importance that patients suspected of chromosomal aberrations undergo chromosomal analysis. Further advanced chromosomal staining and molecular genetic methods will raise the detection rate of chromosomal aberrations.