The present invention relates to a human PAB II gene containing transcribedpolymorphic GCG repeat, which comprises a sequence as set forth in SEQ IDNO:3, which includes introns and flanking genomic sequence. The allelicvariants of GCG repeat of the human PAB II gene are associated with a diseaserelated with protein accumulation in nucleus, such as polyalanineaccumulation, a disease related with swallowing difficulties, such asoculopharyngeal muscular dystrophy. The present invention also relates to amethod for the diagnosis of a disease with protein accumulation in nucleus,which comprises the steps of: a) obtaining a nucleic acid sample of saidpatient； and b) determining allelic variants of GCG repeat of the gene ofclaim 1, and wherein long allelic variants are indicative of a disease relatedwith protein accumulation in nucleus.
