Once in awhile, in the US, you might pick up a case in "white" people, especially from Mediterranean areas (although Thalessemia is much more common).
The reason is that both these disease give some protection from Malaria
But AlJ reports that some of the indigenous tribes of India also have a high rate of the disease
Sickle cell: A silent killer in Chhattisgarh state The hereditary disease kills at least 10,000 children a year in this Indian state.
In India, the disease was first detected in 1952 among indigenous tribes in the Nilgiri Hills of south India. That same year, some migrant labourers working in the tea gardens of Assam state were also diagnosed with the hereditary disease. Of Chhattisgarh's 7.5 million strong indigenous tribal population, at least 20 percent, particularly among the Gond tribe, are affected by sickle cell disease, according to Dr Patra.