A baby girl was only found to have died of a rare hereditary syndrome after her younger brother died of the same disorder two years later, an inquest heard yesterday. Paediatrician Dr Patrick Yuen said 11-month-old Yuen Yee-ting died of carnitine uptake deficiency - or carnitine transport defect - in 1994. The syndrome killed her six-month-old brother, Chun-hin, in January last year - the only instances of it striking in Hong Kong. Fewer than 40 children worldwide suffer from the condition. Parents Yuen So-choi and Tse Shuk-ching are both deficient in carnitine, an enzyme that is crucial for cell activities. Its absence leaves infants weak and they die quickly if they are struck by any minor ailment. The court heard the girl died on February 11, 1994, at St Teresa's Hospital, Kowloon, after suffering a fever and cold for two days. A postmortem examination concluded she died of Reye's syndrome - a viral infection of the upper respiratory tract. But the Coroner's Court reopened investigations when a team at the Prince of Wales Hospital, led by Dr Yuen, started studying the girl's death after her brother died of the same rare condition. Their medical files were sent to an institute in Amsterdam for analysis which confirmed they suffered from the same disorder. Coroner Richard Day recorded a verdict of death by natural causes on Yee-ting. Her parents complained at the inquest about the consultation and treatment she received at St Teresa's. Her father said doctors had not examined her thoroughly. However, Dr Yuen said the hospital had taken appropriate action given the circumstances because the disorder did not show any obvious symptoms. 'Babies normally die in the space of six to 12 hours. There is not much we can do about it,' he said. The couple's third child, 11-month-old Ka-lok, is also a carrier. But Dr Yuen assured the parents he could lead a normal life as his was a recessive case.