Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Private Bag, Rondebosch, 7700, Cape Town, South Africa, African Institute for Mathematical Sciences, 7945 Muizenberg, Cape Town, South Africa and Computational Biology Division, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Medical School, Anzio Road, Observatory, 7925, Cape Town, South Africa.