Characterisation of the human voltage-gated potassium channel gene, KCNA7, a candidate gene for inherited cardiac disorders, and its exclusion as cause of progressive familial heart block I (PFHBI)

Eur J Hum Genet. 2002 Jan;10(1):36-43. doi: 10.1038/sj.ejhg.5200739.


Mutations in genes encoding cardiac ion channels and their subunits are responsible for several genetic cardiac disorders. We characterised the human gene KCNA7, encoding the voltage-gated potassium channel Kv1.7 and compared its coding sequence with that of the mouse orthologue, kcna7. Both genes are encoded by two exons separated by a conserved intron, unlike all the other Kv1-family genes that contain intronless coding regions. KCNA7 and kcna7 encode proteins of 456 amino acid residues that share >95% sequence identity, and the mouse channel has biophysical and pharmacological properties closely resembling the ultra-rapidly activating delayed rectifier (I(Kur)) in cardiac tissue. Using reverse transcriptase-PCR, KCNA7 mRNA was detected in adult human heart. We determined that KCNA7 resides on chromosome 19q13.3 in a region that also contains the progressive familial heart block I (PFHBI) locus. Direct sequencing of KCNA7's coding sequence in PFHB1-affected individuals revealed no pathogenic sequence changes, but two single nucleotide polymorphisms detected in exon 2 result in amino acid substitutions. These results provide evidence for the exclusion of this candidate as the PFHB1-causative gene, although mutations in regulatory and non-coding regions cannot be excluded. As ion channel-encoding genes have been implicated in a growing number of genetic conditions, the data presented may facilitate further analysis of the role of KCNA7 and its product in the heart.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • COS Cells
  • Cloning, Molecular
  • DNA
  • Heart Block / genetics*
  • Heart Diseases / genetics*
  • Humans
  • Mice
  • Molecular Sequence Data
  • Potassium Channels / genetics*
  • Potassium Channels / physiology
  • Potassium Channels, Voltage-Gated*
  • Shaker Superfamily of Potassium Channels
  • Trinucleotide Repeats


  • KCNA7 protein, human
  • Potassium Channels
  • Potassium Channels, Voltage-Gated
  • Shaker Superfamily of Potassium Channels
  • DNA

Associated data

  • GENBANK/AF315818