A black Nigerian couple have given birth to a white baby. With blonde curly hair and blue eyes, the girl's appearance has prompted several theories as to its genetic cause.
Ben and Angela Ihegboro already have a son and a daughter, both with dark skin and hair. Mrs Ihegboro described the girl, Nmachi, as a 'miracle', and said her colour didn't matter. However she added: 'still, what on earth happened here?'
One possibility is Nmachi inherited light skin gene variants from her parents. As skin colour is influenced by about 12 different genes, Mr and Mrs Ihegboro could have passed on genes from unknown white ancestors, which in their cases were masked by dark skin variants.
'We are all of us genetic mixtures to some extent and occasionally you'll have a convergence of the pale versions of these genes in African Americans and African Caribbeans who have a mixed black and white ancestry', said Bryan Sykes, Professor of Human Genetics at the University of Oxford, UK. 'But that doesn't seem to be the case here. The parents are Nigerians with little known white ancestry at all'.
Professor Sykes thinks it is more likely Nmachi has a genetic mutation unique to her, which has resulted in her colouring.
Despite reports that the girl does not have albinism, Professor Ian Jackson from the Human Genetics Unit at the Medical Research Council, UK, told the BBC this was a potential cause: 'This is perhaps one of the most common recessive disorders in Nigeria, and we have to remember that it comes in different forms'.
Albinism affects one in 20,000 people, and is graded from type one to four. 'In Type 2 we would see creamy skin and yellow hair or light brown, which in some cases would darken with age', added Professor Jackson.
Both parents could have been carrying the genes for albinism without it having surfaced in any family members for many years.