We report a novel mutation detected in a 33 year old Chinese man with congenital bilateral absence of the vas deferens (CBAVD), a past history of pulmonary meliodosis infection and a past history of bronchiolitis obliterans organising pneumonia. A novel splice site mutation in intron 6b (1001+5 G-->A) in the homozygous state was identified, and was predicted to lead to inefficient splicing. He was also homozygous at all intragenic and flanking polymorphic markers. Quantitative realtime PCR analysis showed that there were 2 copies of the CFTR gene present, ruling out the possibility of a deletion, and strongly suggesting the possibility of uniparental isodisomy involving at least a part of chromosome 7.