FDA approves lifesaving therapy for rare genetic condition for children

On Monday, the FDA approved the first treatment for metachromatic leukodystrophy, a rare and deadly disorder that kills infants before age 7.

The one-time Lenmeldy treatment inserts defective genes into stem cells from MLD patients using a harmless virus. After being put back into the patient, the restored cells create an enzyme missing in youngsters with the illness.

The tailored therapy and small number of cases contribute to the high anticipated cost: It may cost $3.9 million, making it the world's most costly medication, according to analysts.

Sulfatide-degrading enzymes are absent in children with MLD, a hereditary condition. These fatty deposits poison nerves, causing movement and thinking loss.

MLD babies initially develop normally but lose the ability to walk and talk at age 2. The condition swiftly develops, leaving children vegetative.