This 21-year-old man stuck in a pensioner body due to rare genetic condition (photos, video)

- A 21-year-old Indian man has the body of a 160-year-old

- He suffers from progeria, which causes his body to age eight times faster than normal

- He has surpassed the life expectancy of progeria sufferers

A 21-year-old man from Hanumanganj in India has the body of a 160-year-old pensioner, prompting people to refer to him as the world's oldest "Benjamin Button."

Rupesh Kumar was born with Hutchinson-Gilford progeria, a rare condition that affects just one on eight million people around the world.

Progeria causes one's body to age eight times faster than normal. Sufferers are sometimes referred to as "Benjamin Button" after a fictional character who was born old.

Man, 21, with rare genetic condition has body of 160-year-old pensioner

Rupesh Kumar suffers from progeria, a condition that causes his body to age eight times faster than normal

At 21, Rupesh is the oldest known progeria sufferer in the world, having surpassed a life expectancy experts say is between 13 and 15 years. He weighs only 19kg.

His parents, father Ramapati Kumar, 45, and mother Shanti Devi, said in an interview that they first noticed something amiss with Rupesh's growth when he was two years old.

Progeria is rare and affects just one in eight million people

Ramapati said: "It all started with frequent headaches and stomach pains when he was very small. We took him to several doctors, but none of them could diagnose his condition."

However, experts say progeria is incurable. Rupesh's doctor, Dr Yugantar Pandey, said Rupesh's eyes have receded back into his eye sockets, his hair stopped growing and his skin sagged and became pale.

Rupesh with his father Ramapati Kumar and mother Shanti Devi

Dr Pandey also said Rupesh's muscles lost strength, adding: "This is a genetic problem that occurs due to mutation of genes."

Unfortunately, Ramapati said some circus managers played on their desperation and offered them money to put Rupesh on display, which they rejected. However, they have not given up hope of curing their son of the disease.