A Novel Splice-site Allelic Variant is Responsible for Wilson Disease in an Omani Family

The objective of this study was to characterise Wilson's Disease (WD) [OMIM 277900] genetically and test for allelic variants in the copper transport gene (ATPase, Cu(++) transporting, beta polypeptide, ATP7B) responsible for the disease in an Omani family.

Three index patients from an Omani family had been previously diagnosed with WD. All three patients suffered neurological symptoms and signs. Forty-six relatives in the family were screened for WD. Eleven more individuals were positive, but asymptomatic.

Thirteen non-disease-causing allelic gene variants, described previously, were identified in the ATP7B gene from 46 family members. A putative novel disease-causing splice-site variant (c.2866-2A>G), which has not been reported previously, was detected in this family. It is located upstream of exon 13 which encodes part of transmembrane copper channel (Ch/Tm6). Reverse transcription polymerase chain reaction was used to amplify a complementary DNA (cDNA) fragment containing exons 12, 13 and 14. Exon 13 was entirely skipped from the transcript which probably would result in a defective ATP7B protein.

A new ATP7B splice-site allelic variant, found among the 14 WD patients segregated with the disease in a recessive manner, suggests it is a disease-causing variant.