Fortune J Rheumatol 2020; 2 (2): 061-066 DOI: 10.26502/fjr.26880018 Fortune Journal of Rheumatology 61 Case Report Osteogenesis Imperfecta-Serine Replacing Glycine in the COL1A1 Gene-A New Establishment in Genetics Usman Tauseef 1 , Mohsina Ibrahim 1 , Muhammad Sohaib Asghar 2* , Abubakar Tauseef 2 , Maryam Zafar 2 , Uzma Rasheed 3 , Gul Muhammad Memon 3 , Mohammed Akram 3 1 National Institute of Child Health, Karachi, Pakistan 2 Dow University of Health Sciences, Karachi, Pakistan 3 Liaquat National Hospital and Medical College, Karachi, Pakistan * Corresponding Author: Muhammad Sohaib Asghar, Dow University Hospital, Dow University of Health Sciences, Karachi, Pakistan, E-mail: sohaib_asghar123@yahoo.com Received: 14 March 2020; Accepted: 27 March 2020; Published: 03 April 2020 Citation: Usman Tauseef, Mohsina Ibrahim, Muhammad Sohaib Asghar, Abubakar Tauseef, Maryam Zafar, Uzma Rasheed, Gul Muhammad Memon, Mohammed Akram. Osteogenesis Imperfecta: Serine Replacing Glycine in the COL1A1 Gene-A New Establishment in Genetics. Fortune Journal of Rheumatology 2 (2020): 061-066. Abstract Osteogenesis Imperfecta (OI) is a genetic disorder of bone fragility. In most cases, genetic testing is not usually done either due to a lack of availability or unaffordability. In our study, we looked for a rare gene variant in a patient with Osteogenesis Imperfecta type 1. Our patient who was a 6-month-old baby boy presented to us with multiple bone fractures, blue sclera, umbilical hernia with the absence of dentinogenesis Imperfecta, and hypercalcemia. A gene sequencing came out to be COL1A1 positive having a nucleotide change of glycine acid mutation replaced by serine, which was a unique feature in a patient of OI, and as Glycine was critical for COL1A1 gene, its replacement leads to the patient presented as a homozygous case of OI. OI is usually diagnosed on a history of recurrent spontaneous fractures and characteristic features like blue sclera, short stature, and deformities of long bones or spine. Keywords: Osteogenesis; Mutation; Bone Disease; Genetic; Congenital Abnormalities; Deformities 1. Introduction Osteogenesis Imperfecta is a rare genetic disorder described by Lobstein as Fragilatus Osseum which was later renamed as osteogenesis Imperfecta by Vrolik. Its incidence is 1 in 10000-20000 births [1-3]. It manifests