An inquest into the death of a 15-year-old Norwich boy heard that the circumstances were so rare that most surgeons would never come across them.

Misbaur Choudhury, from Newbigin Road, Thorpe Hamlet, was pronounced dead at the Norfolk and Norwich University Hospital on March 24 last year.

Since birth he had suffered from cri-du-chat syndrome, a rare genetic disorder that only affects one in 50,000 live births.

The disorder left the boy with severe learning and physical difficulties and a possible consequence of the disorder is a distended bowel.

On March 14, 2011, a teacher from the Hall School in Norwich took the boy to the children's assessment unit at the hospital, after he had come back from respite care feeling unwell.

He was discharged but on March 17 he was re-admitted as an emergency with an abdominal distension. After an operation he appeared to be getting better, but on March 23 he was again distressed and his mother agreed to another operation. The following day the boy's condition was very grave and he was pronounced dead at about 1.50pm.

Yesterday's Norwich inquest heard that at the time of the second operation his distended large bowel had twisted on its axis.

The cause of death was given as perforated infarcted colonic volvulus with cri-du-chat syndrome as a contributory factor.

Azad Mathur, a consultant paediatric surgeon at the N&N, told the inquest: 'Large bowel volvulus is very rare and American surgeons have recorded that it has only happened about 60 times in 60 years. Very few surgeons will see it in their lifetimes.'

The teenager's mother, Alima Choudhury, speaking through a Bengali interpreter, said her son was a happy and cheerful boy, despite his condition. Norfolk coroner William Armstrong recorded a verdict that the teenager died as a result of complications arising from a very rare natural medical condition.