Kolkata: Headaches of abnormal nature should not be ignored as it may be an indication of a rare brain syndrome, suggested an expert on Wednesday. With the highest number of incidences reported from Japan, Moya Moya syndrome narrows main arteries in the brain, thereby blocking the blood flow and causing severe blood clots.

Headache is the primary and initial symptom of this rare disease. "Any headache of unusual manner should not be ignored and be taken into consideration as soon as possible," said R P Sengupta, chairman and managing director, Institute of Neurosciences, Kolkata, that treated 25 cases of Moya Moya in the past three years.

While the average count of people being affected by the disease in America is 0.08 per 100,000 people, Japan witnesses 0.35 per 100,000 people falling prey to Moya Moya on an average.

Terming it "an enigma", Sengupta explained that the manner in which the disease develops is yet to be discovered. "The condition is believed to be hereditary, more common in women than in men," said Sengupta. The resulting blockage, if not treated, may lead to strokes, impairment and even death.