Clinical Investigation and Genetic Characterization of Congenital Skeletal Dysplasia

Abstract

Human skeletal dysplasia is a heterogenous and complex group of congenital bone diseases, caused by mutations in genes involved in embryonic development of skeletogenesis. It affects axial, appendicular as well as craniofacial skeleton, both in terms of phenotypes and number of bones. In the present research study, thirteen families, exhibiting various forms of congenital skeletal dysplasia were investigated at clinical and molecular level to identify diseases causing variants. All the families were sampled from district Swabi, Khyber Pakhtunkhwa, Pakistan. After getting informed consent, pedigrees were drawn and blood was collected in EDTA tubes. X-rays were then taken from affected family members in local hospital to assess disease phenotype. DNA was extracted from available family members using either Chloroform-Phenol method or commercially available kit. DNA of one affected member from each family (except family L &M) was proceeded for whole exome sequencing and identified pathogenic variant was segregated using Sanger sequencing. In family L & M, highly polymorphic microsatellite markers-based homozygosity mapping was performed and the linked genes were Sanger sequenced to identify disease causing variant. Genetic analysis identified reported variants in BBS5, EVC, IDUA, GALNS, CHST3, HOXD13, GJA1 and NPR2 genes, while novel variants in ROR2, GNPTG, NPR2 and BMPR1B genes. Sanger sequencing confirmed segregation of pathogenic variants in respective family members. The identified variants expand mutational and clinical spectrum of congenital skeletal dysplasia in Pakistani families, which will further help in future diagnosis and genetic counseling. The research work presented in thesis has been published in reputed scientific journals. 1. Sequence variants in different genes underlying Bardet-Biedl syndrome in four consanguineous families. Ali, A, Abdullah,....Wasim Ahmad* (2023). Mol Biol Rep Abstract Clinical Investigation and Genetic Characterization of Congenital Skeletal Dysplasia xv 2. Clinical and Genetic Investigation of Fourteen Families with Various Forms of Short Stature Syndromes. Fati Ullah…….Amjad Ali…..Wasim Ahmad* (Clinical Genetics. 10.1111/cge.14550). 3. Phenotypic demarcation of a complex disorder in a family with a homozygous variant in EVC and a heterozygous variant in ROR2 gene. Amjad Ali*, Shabir Hussain, Petra Loid, Safeer Ahmad, Mari Muurinen, Imranullah, Wasim Ahmad, Outi Makitie (Write up). 4. Clinical and Molecular Characterization of Acromesomelic Dysplasia- Maroteaux Type in Pakistani Families. Amjad Ali*,… Outi Makitie, Wasim Ahmad, Imran Ullah. (Write up). 5. Sequencing BMPR1B Gene in Consanguineous Pakistani Families Exhibiting Acromesomelic Dysplasia- Grebe Type. Amjad Ali*,…. Imran Ullah. (Write up). 6. Clinical and Molecular Studies of Lysosomal Storage Diseases in Consanguineous families. Amjad Ali, Shabir Hussain, Wasim Ahmad, Imranullah. (Write up).