Rabia Shahid1, Muhammad Yasin1, Zia Ur Rehman1, Humaira Jadoon2, Haleema Tahir1, Neelam Meraj1, Niamat Khan1, Maria Zubair1, Irba Zulfiqar1, Maha Nowshid1, Arfa Azeem1, Musarrat Jabeen3, Abdul Hameed4, Shamim Saleha5. 1. Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan. 2. Department of Obstetrics & Gynecology, Ayub Medical Institute, Abbottabad, 22010, Khyber Pakhtunkhwa, Pakistan. 3. Department of Obstetrics and Gynecology, Liaqat Memorial Hospital, KIMS, Kohat, 26000, Khyber Pakhtunkhwa, Pakistan. 4. Institute of Biomedical and Genetic Engineering (IBGE), Islamabad, 44000, Pakistan. 5. Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan. shamimsaleha@yahoo.com.
Abstract
INTRODUCTION: The CGG repeats in the 5' untranslated region of the fragile X mental retardation 1 gene (FMR1) gene shows increased instability upon maternal transmission. Maternal FMR1 intermediate (45-54 repeats) and premutation (PM: 55-<200 repeats) alleles usually expand to full mutation (>200 repeats) alleles in offspring and consequently, cause fragile X syndrome (FXS) in them. METHODS: In a prospective cohort study, Pakistani pregnant women in prenatal care were first screened for FMR1 expanded alleles. In the follow-up, pregnancy outcomes in women carrying FMR1 expanded alleles were recorded and their newborn offspring were also screened for FXS. RESULTS: In a total of 1950 pregnant women, 89 (4.6%) were detected carriers for FMR1 expanded alleles; however, rates of detection of expanded alleles were found significantly high in women with a history of FXS. In addition, miscarriages and birth of affected newborns with FXS were significantly more common in women carrying large size PM alleles and had a history of FXS (P = 0.0494 and P = 0.0494, respectively). CONCLUSIONS: The current study provides the first evidence of screening Pakistani pregnant women for FMR1 expanded alleles in prenatal care. Moreover, the miscarriage was also detected as a clinical predictor for FXS. IMPACT: Offspring would have a higher risk of developing FXS due to maternal FMR1 alleles expansions during transmission. This is the first prospective cohort study in Pakistan for finding FMR1 allelic status of pregnant women and their newborn offspring in follow-up. The robust offspring risk for FXS estimated in this study may be valuable information for genetic counseling of women carriers for FMR1 expanded alleles. The family history and miscarriage were detected as effective indicators for FXS carrier screening in Pakistani women.
INTRODUCTION: The CGG repeats in the 5' untranslated region of the fragile X mental retardation 1 gene (FMR1) gene shows increased instability upon maternal transmission. Maternal FMR1 intermediate (45-54 repeats) and premutation (PM: 55-<200 repeats) alleles usually expand to full mutation (>200 repeats) alleles in offspring and consequently, cause fragile X syndrome (FXS) in them. METHODS: In a prospective cohort study, Pakistani pregnant women in prenatal care were first screened for FMR1 expanded alleles. In the follow-up, pregnancy outcomes in women carrying FMR1 expanded alleles were recorded and their newborn offspring were also screened for FXS. RESULTS: In a total of 1950 pregnant women, 89 (4.6%) were detected carriers for FMR1 expanded alleles; however, rates of detection of expanded alleles were found significantly high in women with a history of FXS. In addition, miscarriages and birth of affected newborns with FXS were significantly more common in women carrying large size PM alleles and had a history of FXS (P = 0.0494 and P = 0.0494, respectively). CONCLUSIONS: The current study provides the first evidence of screening Pakistani pregnant women for FMR1 expanded alleles in prenatal care. Moreover, the miscarriage was also detected as a clinical predictor for FXS. IMPACT: Offspring would have a higher risk of developing FXS due to maternal FMR1 alleles expansions during transmission. This is the first prospective cohort study in Pakistan for finding FMR1 allelic status of pregnant women and their newborn offspring in follow-up. The robust offspring risk for FXS estimated in this study may be valuable information for genetic counseling of women carriers for FMR1 expanded alleles. The family history and miscarriage were detected as effective indicators for FXS carrier screening in Pakistani women.
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