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NF1 Mutations and Clinical Manifestations in Neurofibromatosis Type 1 Patients in Tamil Nadu, South India

Author Affiliations

  • 1Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore-641046, India

Int. Res. J. Biological Sci., Volume 5, Issue (8), Pages 38-44, August,10 (2016)

Abstract

Neurofibromatosis type 1 (NF1) is a genetic disorder affecting approximately 1 in 3000 individuals. It is caused by heterozygous inactivation of the NF1 a tumor suppressor gene or deletions of the entire NF1 gene. This study exemplifies the clinical heterogeneity of 13 Indian patients with NF1 and highlights the variations in sites and types of mutations in NF1 gene in this population. The DNA was extracted from the blood samples and the entire coding region of NF1 gene was amplified and sequenced by the Sanger method. In the present study, the frequencies of neurofibromas and plexiform neurofibromas were 92.3% and 30.7% respectively. 84.6% had a short stature and 38.5% had a macrocephaly. Café-au-lait spots were in all the cases while scoliosis was in only 2 patients. 53.8% had a frequent headache and 23% had facial dysmorphism. All NF1 mutations identified in 11 patients in our study population have been reported in previous studies and no novel mutation has been detected. NF1 mutations were detected in exons 4, 13, 21, 29, and 46. The frequencies of point mutations were 36.4% nonsense, 36.4% missense and 27.2% frameshift. Variable expression of the same NF1 mutation made identification of genotype-phenotype correlations a daunting task.

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