See page 5 of the the following document for an explanation of the difference between GCSE and IGCSE qualifications:
http://www.cie.org.uk/docs/recognition/Recognition%20and%20Equivalency...
"In short, IGCSE examinations are tailored for a multi-cultural, multi-lingual audience in a way that UK GCSE examinations are not. Grade for grade, though, they are aligned to the standards of the UK GCSE, and this has always been recognised as the case by ‘users’ of the qualifications. UCAS and universities in the UK and overseas recognise IGCSE qualifications as equivalent grade for grade with UK GCSE qualifications."
