Two-year-old Ava Fenton may be called lucky when she starts attending school and she reveals that her parents never yell at her.

However, the reason that they never do is that little Ava has a very rare condition that could cause her heart to stop if they do. The condition is set off by extreme emotions, like fear, upset, and anger, and her parents fear that they can trigger it by raising their voices at her.

Ava Fenton suffers from an extreme case of reflex anoxic seizures, a condition that affects about 8 of every 1,000 preschool-aged children. If Ava is upset, injured, or even tired, that too could set off the condition. If a reflex anoxic seizure is triggered, Ava's heart could slow and her brain could lose its supply of blood. In Ava's particular case, crying is a sign of the onset of a fit.

The condition makes it difficult for her parents to discipline her, who say that they did not want to be type to "mollycoddle" their children, but have no other choice. "It was really hard to discipline Ava. We had to pick our battles," her mother Natalie said to Daily Mail. "We only told her off when she did something that was dangerous, for example playing behind the television near the electric cables. We always had a real feeling of guilt afterward as we knew she would pass out."

The first fit occurred when Ava was six months old. Her father Paul was teaching her how to sit up when she fell over and knocked her head. She let out a cry before suddenly falling silent, turning white, and appearing to stop breathing.

When she regained consciousness, doctors told the Fenton family that she probably just held her breath. But her mother Ms. Fenton, a midwife, believed that there was more to the story. Over the course of ten months, Ms. Fenton refused to leave her daughter's side, and Ava had episodes about five times a day, each of which lasted about 40 seconds.

A fit that lasted 20 minutes after she tripped and hit her head caused doctors to change their diagnosis. The tests revealed that she had reflex anoxic seizures. She was fitted with a pacemaker which stops her heartbeat from dipping below 80 beats per minute.