Complex sentence: However, nearly all reported cases of Costeff syndrome has been in individuals of Iraqi Jewish origin, all of whom share the same splice site founder mutation, though the severity of symptoms varies with the individual.
Split into simpler sentences: However, nearly all reported cases of Costeff syndrome has been in individuals of Iraqi Jewish origin, all of whom share the same splice site founder mutation. Though the mutation is the same within this population, the severity of symptoms varies with the individual.