Mutations in the PIG-A gene causing paroxysmal nocturnal hemoglobinuria are mainly of the frameshift type.
Paroxysmal nocturnal hemoglobinuria is an acquired hemolytic anemia associated with somatic mutations in the X-linked gene PIG-A, which encodes a protein involved in the biosynthesis of glycosyl phosphatidylinositol anchors. To further elucidate the molecular basis of paroxysmal nocturnal hemoglobinuria, we have worked out a systematic and relatively rapid methodology to scan for mutations in the entire coding region of the PIG-A gene. By this methodology, we have identified 15 different somatic mutations in 12 patients. The mutations were spread throughout the entire PIG-A-coding region. Of the mutations, 10 caused frameshifts, 6 caused small deletions, 3 caused small insertions, and 1 caused deletion-insertion. Five single base pair substitutions caused three missense mutations, one nonsense mutation, and one defect in the donor splice site of intron 4. In each of 3 patients, two independent mutations were identified. The predominance of frameshift mutations may reflect selection for somatic mutations giving rise to clones with a completely nonfunctional PIG-A protein.
Department of Haematology, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
K
K
Nafa
P J
PJ
Mason
P
P
Hillmen
L
L
Luzzatto
M
M
Bessler
D000595:Amino Acid Sequence; D001483:Base Sequence; D004252:DNA Mutational Analysis; D005260:Female; D016368:Frameshift Mutation; D005796:Genes; D006457:Hemoglobinuria, Paroxysmal / Q000235:genetics*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics*; D008969:Molecular Sequence Data; D017354:Point Mutation; D017384:Sequence Deletion
D008565:Membrane Proteins; C080086:phosphatidylinositol glycan-class A protein