MAHA SAAD ZAKI, a professor of clinical genetics, ushers Ahmed, Fatima and their family into her room at Egypt’s National Research Centre. At least three of their six children have a rare neurological illness that manifests itself around age four, causing mental retardation, loss of the use of their limbs and, later, death. The couple’s nine-year-old daughter slumps, twitching. This congenital illness has appeared because, as well as being husband and wife, Ahmed and Fatima are also first cousins (their names have been changed).
Cases like these are all too common in the Middle East and north Africa. Marrying a close relative markedly increases the chance that both parents are carriers of dangerous recessive genes, which can then cause disease when a child inherits a copy of the gene from both parents, as will happen in 25% of cases. The gamut of such illnesses runs from known ones such as microcephaly (in which children have unusually small heads) cystic fibrosis and thalassaemia, a blood disorder, to wholly new disorders. “Ninety percent of the cases I see are caused by consanguineous...Continue reading
Source: Middle East and Africa http://ift.tt/1OxiuNM
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