Gene that causes stunted growth in babies found

Scientists have identified a gene mutation responsible for IMAGe syndrome, a rare disorder that causes stunted growth in babies, a finding they say could lead to new treatments and tests for the multi-system disorder.

The disorder, which makes babies end up with a smaller than normal body and organs that often leads to potentially life-threatening complications, was discovered some 20 years ago. But what causes the disease has so far eluded scientists. Eric Vilain of the University of California, Los Angeles, had first identified the disorder in France in two boys, aged three and six, who were dramatically short for their ages.

“I never found a reason to explain these patients’ unusual set of symptoms. I’ve been searching for the cause of their disease since 1993,” Vilain.

He finally found the reason behind it after studying the genetics of an Argentinean family and several other patients with the syndrome. A total of 20 IMAGe patients have been identified with the syndrome across the globe, and many have provided samples for genetic testing. Vilain and his team compared the genomes of affected patients in the family with their non-affected relatives. They found the mutation that causes IMAGe in a gene called CDKN1C. The mutation in the CDKN1C gene “consistently appeared in every family member affected by IMAGe syndrome,” Vilain said.

“We were a little surprised, though, because the mutation was located on a gene previously recognised as causing Beckwith-Wiedemann syndrome (a growth disorder that causes large body size and organs),” he added.

Those with the disorder also have an increased likelihood of developing tumours, the most common of which are Wilm’s tumour (a kidney cancer in kids) and adrenal carcinoma, the researchers reported in the journal Nature Genetics.

This disease is more prevalent than IMAGe, affecting about 1 in 12,000 to 15,000 newborns worldwide; about one in five infants with the syndrome dies early in life, according to the NIH.

“Finding dual functions in one molecule is an unusual biological phenomenon. These two diseases are polar opposites of each other, Vilain said.

“When the mutation appeared in the slim section we identified, the infant developed IMAGe syndrome. If the mutation fell anywhere else in the gene, the child was born with Beckwith-Wiedemann. That’s really quite remarkable.”