Mucopolysaccharidosis type IVA: common double deletion in the N-acetylgalactosamine-6-sulfatase gene (GALNS).

Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive disorder caused by a deficiency in N-acetylgalactosamine-6-sulfatase (GALNS). We found two separate deletions of nearly 8. 0 and 6. 0 kb in the GALNS gene, including some exons.
There are Alu repetitive elements near the breakpoints of the 8. 0-kb deletion, and this deletion resulted from an Alu-Alu recombination.
The other 6. 0-kb deletion involved illegitimate recombinational events between incomplete short direct repeats of 8 bp at deletion breakpoints.
The same rearrangement has been observed in a heteroallelic state in four unrelated patients.
This is the first documentation of a common double deletion a gene that is not a member of a gene cluster.

