α0-Thalassemia Due to a 90.7 kb Deletion (– –NFLD)

Abstract

We report an α0-thalassemia (α0-thal) trait in Newfoundlanders caused by a novel 90.7 kb deletion. The deletion, designated the Newfoundland deletion (– –NFLD), removes both the HBA2 and HBA1 genes, while leaving the HBZ gene intact. The 5′ deletion endpoint is within the HBAP1 pseudogene, approximately 3.7 kb upstream of the HBA2 gene. The 3′ deletion endpoint is approximately 82.5 kb downstream of the HBA1 gene, within the second intervening sequence (IVS-II) of the FAM234A gene. This is the second α0-thal deletion reported in Newfoundland families of northern European descent.