THE father of a little boy struck down by a devastating rare genetic disease has welcomed a landmark Commons vote to allow “three-parent” children to be conceived.

The new IVF technique is designed to prevent incurable mitochondrial disease being passed from mother to baby in the womb.

Mitochondria are tiny rod-liked power plants in the body’s cells which, when damaged, can affect major organs and cause symptoms ranging from poor vision to diabetes and muscle wasting.

Combining the DNA of the mother and father with another female who does not carry the defective gene would protect the unborn child.

Three-year-old Maxwell Smith was born healthy and grew and developed normally.

His parents Pete and Emma, from Storrington, had no concerns until Maxwell was about eight months old and he could not bear any weight on his legs.

Doctors did not think there was a problem at first but Maxwell then went off his food and developed a rash so his parents took him to hospital.

It was discovered he had severe tonsillitis and he then developed complications after his milk started going into his lungs instead of his stomach.

Maxwell was transferred to St George’s Hospital in London where he underwent numerous tests and he was diagnosed with mitochondrial disease.

He could no longer breathe on his own so had an operation to attach a tube so he could be on a ventilator for 24 hours a day. Maxwell will be connected to the device for the rest of his life.

Mr Smith, 40, and Mrs Smith, 35, have dedicated their lives to caring for their son.

The youngster needs to be monitored day and night as 70% of his muscles do not work and he cannot do anything for himself, including swallowing and moving about.

The Smiths are supported by the NHS but bear the brunt of his care themselves.

Mr Smith said: “Maxwell is a very happy little boy. He can nod his head, blow kisses and wave his hand.

“It is very hard work but obviously Maxwell is always our first priority and we love him so much.

“The decision to allow the three-parent baby is fantastic.

“Maxwell is very important to us and we will always give him the best of everything but if there is a chance that something could be done so that parents and children would not have to experience this disease then that can only be a good thing.

“If we ever did think about having another child then using this IVF approach is something we would consider.

“In the meantime we are focusing on Maxwell. We don’t know what the future holds but we will enjoy every moment we have with him.

“It is a long road but he is happy and so we’re happy. That is what it comes down to.”