Identification of mutations in and in Sandhoff and Tay-Sachs diseases: a new large deletion caused by elements in .

G gangliosides are a group of lysosomal lipid storage disorders that are due to mutations in , and . In our study, 10 patients with these diseases were enrolled, and Sanger sequencing was performed for the and genes. The results revealed one known splice site mutation (c.346+1G>A, IVS2+1G>A) and three novel mutations (a large deletion involving exons 6-10; one nucleotide deletion, c.622delG [p.D208Ifsx15]; and a missense mutation, c.919G>A [p.E307K]) in . In , one known mutation (c.1597C>T [p.R533C]) and one variant of uncertain significance (c.619A>G [p.I207V]) were identified. Five patients had c.1597C>T in , indicating a common mutation in south Iran. In this study, a unique large deletion in was identified as a homozygous state. To predict the cause of the large deletion in , RepeatMasker was used to investigate the elements. In addition, to identify the breakpoint of this deletion, PCR was performed around these elements. Using Repeat masker, different elements were identified across , mainly in intron 5 and intron 10 adjacent to the deleted exons. PCR around the elements and Sanger sequencing revealed the start point of a large deletion in Sz6 in the intron 6 and the end of its breakpoint 73 nucleotides downstream of Jo in intron 10. Our study showed that is an -rich gene that predisposes individuals to disease-associated large deletions due to these elements.