Iqra Ghulam Rasool1, Muhammad Yasir Zahoor2, Muhammad Iqbal3, Aftab Ahmad Anjum4, Fatima Ashraf1, Hafiz Qamar Abbas1, Hafiz Muhammad Azhar Baig3, Tariq Mahmood5, Wasim Shehzad1. 1. Molecular Biology and Forensic Laboratory, Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Lahore, 54000, Pakistan. 2. Molecular Biology and Forensic Laboratory, Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Lahore, 54000, Pakistan. yasir.zahoor@uvas.edu.pk. 3. Department of Biotechnology, The Islamia University of Bahawalpur, Bahawalpur, Pakistan. 4. Institute of Microbiology, University of Veterinary and Animal Sciences, Lahore, Pakistan. 5. Department of Statistics and Computer Science, University of Veterinary and Animal Sciences, Lahore, Pakistan.
Abstract
BACKGROUND: Intellectual disability (ID) is a heterogeneous disorder affecting 1-3% of the population. Elucidation of monogenic variants for ID is a current challenge. These variants can be better demonstrated in consanguineous affected families. OBJECTIVE: The study was designed to find the genetic variants of ID in consanguineous families. METHODS: We analyzed five unrelated consanguineous Pakistani families affected with ID using whole exome sequencing (WES). Data was analyzed using different bioinformatics tools and software. RESULTS: We mapped four variants including three novels in four different ID known genes. Each variant is found in a different family, co-segregating with a recessive pattern of inheritance. The novel variants found are; c. 2_4del (p.?) mapped in ROS1 and c. 718G>A (p.Gly240Arg) in GRM1. Another novel causative variant, c.2673del (p.Gly892Aspfs*17) identified in COL18A1 in a recessive form, a gene reported for Knobloch syndrome that manifests ID along with typical retinal abnormalities, and this phenotype was confirmed on reverse phenotyping. A mutation c.2134C>T (p.Arg712*) in TRAPPC9 has been found first time in the homozygous recessive form in our enrolled three affected siblings while it was previously reported in compound heterozygous form in a Caucasian descent. While fifth family remained unsolved. CONCLUSION: These mutations in four different genes with a recessive inheritance would be a contribution to the disease variant database of this devastating disorder.
BACKGROUND: Intellectual disability (ID) is a heterogeneous disorder affecting 1-3% of the population. Elucidation of monogenic variants for ID is a current challenge. These variants can be better demonstrated in consanguineous affected families. OBJECTIVE: The study was designed to find the genetic variants of ID in consanguineous families. METHODS: We analyzed five unrelated consanguineous Pakistani families affected with ID using whole exome sequencing (WES). Data was analyzed using different bioinformatics tools and software. RESULTS: We mapped four variants including three novels in four different ID known genes. Each variant is found in a different family, co-segregating with a recessive pattern of inheritance. The novel variants found are; c. 2_4del (p.?) mapped in ROS1 and c. 718G>A (p.Gly240Arg) in GRM1. Another novel causative variant, c.2673del (p.Gly892Aspfs*17) identified in COL18A1 in a recessive form, a gene reported for Knobloch syndrome that manifests ID along with typical retinal abnormalities, and this phenotype was confirmed on reverse phenotyping. A mutation c.2134C>T (p.Arg712*) in TRAPPC9 has been found first time in the homozygous recessive form in our enrolled three affected siblings while it was previously reported in compound heterozygous form in a Caucasian descent. While fifth family remained unsolved. CONCLUSION: These mutations in four different genes with a recessive inheritance would be a contribution to the disease variant database of this devastating disorder.