Weekly Current Affairs

Zebrafi sh provide insights into a rare human disease [S&T]

  • Scientists from the Delhi-based CSIR-Institute of Genomics and Integrative Biology are a step closer to bringing hope to children born with a rare disorder — CHARGE syndrome — if the results seen in zebrafi sh are reproducible in humans.
  • About 1 in 20,000 people in the world, and an estimated 50,000 in India alone, are born with CHARGE syndrome — multiple life-threatening problems such as deafness and blindness, heart defects, genital problems and growth retardation and facial bone and nerve defects that cause breathing and swallowing diffi culties.
  • There is a high death rate in the very fi rst year in children born with CHARGE.
  • A mutation in the CHD7 gene is responsible for 60-70 per cent of all CHARGE defects. The expression of the gene peaks in the early stages of embryo development, starting from 2-4 cells.
  • Following fertilization, zebrafi sh embryos are transparent. This allows scientists to observe inside of embryo and watch in real time how various organs develop.
  • An RNA injected into a one-cell embryo interferes with the making of the CHD7 protein, thus producing a zebrafi sh embryo with very similar problems as the human babies with CHARGE syndrome.
  • The researchers found that the CHD7 protein causes CHARGE syndrome by modifying a second gene — sox10.
  • Though CHARGE syndrome is extremely complex with multiple defects, reducing the sox10 protein in CHARGE patients may go a long way in reducing their suffering and improve their chances of survival.