A new drug could be used to allow children with dwarfism to grow to average heights.

The drug ‘Vosoritide’ helps regulate bone development, and has now been shown to boost growth rates in children with achondroplasia - the most common type of dwarfism.

Clinical geneticist Professor Ravi Savarirayan, said achondroplasia is caused by overactivity of a signal that stops growth, and could be likened to overwatering a plant.

“This drug basically kinks the hose so that the plant gets the right amount of water and can resume regular growth,” Prof Savarirayan said.

Achondroplasia is a genetic bone disorder affecting about one in every 25,000 infants. It is caused by a mutation in the FGFR3 gene that impairs the growth of bones in the limbs, the spine, and base of the skull.

The most common health complications experienced by children with achondroplasia are spinal cord compression, spinal curvature and bowed legs. About half of these children will need spinal or other surgery.

“This can mean a lot of time away from school as the child recovers and rehabilitates after surgery, which can affect important social connections,” Prof Savarirayan said.

Unlike other treatments – such as growth hormone and limb-lengthening surgery - that focus on symptoms, vosoritide focuses on the underlying cause of achondroplasia and directly counteracts the effect of the mutation that slows growth.

The study ran over four years across research centres in Australia, France, UK and USA with 35 children assigned to one of four groups receiving daily subcutaneous doses of the drug in increasing amounts.

On average, participants in the trial grew at a 50 per cent faster compared to baseline with no adverse effects on body proportion. Overall bone age was not accelerated implying that this effect, if sustained long-term, might increase final adult height.

The main aims of the Phase 2 trial were to evaluate safety and tolerability of the drug and to determine the best dose for the Phase 3 trials, which are now underway.

The full study is accessible here.