A YEAR ago, American teenager Landon Jones stopped eating.

    Overnight, the 12-year-old’s appetite disappeared without warning, hours after he devoured a pizza and bowl of ice cream.

    Waking up on the morning of Oct. 14, 2013, Landon had lost all sense of hunger and thirst, The Des Moines Register reported.

    The once energetic youngster, who loved nothing more than going out on his bike and playing in the park with his friends and brother, stopped.

    He was sick and suffered dizziness almost 24 hours a day.

    Today Landon’s parents Michael and Debbie are at their wits end, desperate for help to discover what is wrong with their son.

    Their quest for a diagnosis has taken the family to five different cities across the United States. The local pediatrician in Waterloo, Iowa, prescribed antibiotics — but still Jones would not eat or drink.

    Michael and Debbie Jones took their son to Rochester in Minnesota where experts at the world-renowned Mayo Clinic examined Landon’s case.

    But their frustrating search has, so far, produced no answers.

    The National Institutes of Health in the United States is now considering offering Landon an appointment — they only examine the rarest of cases each year.

    Landon last year had shed 16 kg, plummeting from 47 kg to 31 kg.

    Michael and Debbie Jones have tried everything they can think of to encourage their son to eat. But the 12-year-old rarely eats more than a bite of his sandwich at lunch and a few crisps.

    While his younger brother Bryce, 9, bounds in from school each day to play with the family’s dog, lethargic Landon prefers to lie on the sofa.

    In the last year he has missed 65 days of school.

    The next step, the Jones say, is to insert a feeding tube, to help nourish Landon directly through his stomach.

    Michael Jones said they believe their son’s illness is linked to the hypothalamus in Landon’s brain, malfunctioning.

    The size of a flattened pea, it regulates hunger and thirst as well as body temperature, blood pressure and sleep cycles.

    Dr. Marc Patterson, a child neurologist at the Mayo Clinic, said Landon’s may be the only case of its kind in the world.

    (SD-Agencies)