Distribution and characterization of a Sandhoff disease-associated 50-kb deletion in the gene encoding the human beta-hexosaminidase beta-chain.
A 50-kb deletion was demonstrated in the gene encoding for the beta-subunit of human hexosaminidase (HEXB), using field inversion gel electrophoresis (FIGE) of SfiI-digested chromosomal DNA from patients with Sandhoff disease. We investigated 14 patients from different parts of Europe and found no deletion in 5 patients, 2 patients homozygous for the deletion, and 7 patients with the deletion in one allele. The distribution of the 50-kb deletion was approximately in agreement with the Hardy-Weinberg equilibrium. The deletion was characterized using chromosomal DNA from one of the two homozygous patients. Restriction fragments were hybridized with a 1.6-kb (almost complete) and a 0.4-kb (5') HEXB cDNA clone. It appeared that the deletion started in intron 5, extending in the 5' direction and causing the loss of exon 1-5 and the promoter area of the HEXB gene.
Bikker
H
H
Department of Experimental Medicine, Academic Medical Centre, Amsterdam, The Netherlands.
van den Berg
F M
FM
Wolterman
R A
RA
Kleijer
W J
WJ
de Vijlder
J J
JJ
Bolhuis
P A
PA
D002872:Chromosome Deletion; D005060:Europe; D005820:Genetic Testing; D054819:Hexosaminidase B; D006720:Homozygote; D006801:Humans; D012150:Polymorphism, Restriction Fragment Length; D015183:Restriction Mapping; D012497:Sandhoff Disease / Q000235:genetics*; D001619:beta-N-Acetylhexosaminidases / Q000235:genetics*
D054819:Hexosaminidase B; D001619:beta-N-Acetylhexosaminidases