Damage to the protective myelin covering the nerves results in progressive worsening of brain and nervous system functions, including: 
Loss of the ability to detect sensations, such as touch, pain, heat and sound
Loss of intellectual, thinking and memory skills
Loss of motor skills, such as walking, moving, speaking and swallowing
Stiff, rigid muscles, poor muscle function and paralysis
Loss of bladder and bowel function
Gallbladder problems
Blindness
Hearing loss
Seizures
Emotional and behavioral problems, including unstable emotions and substance misuse
 Each form of metachromatic leukodystrophy occurs at a different age and can have different initial signs and symptoms and rates of progression: 
Late infantile form. This is the most common form of metachromatic leukodystrophy, starting around 2 years of age or younger. Progressive loss of speech and muscle function occurs rapidly. Children with this form often do not survive beyond childhood.
Juvenile form. This is the second most common form and starts in children between 3 and 16 years of age. Early signs are behavior and cognitive problems and increasing difficulty in school. Loss of the ability to walk may occur. Although the juvenile form doesn't progress as fast as the late infantile form, survival is generally less than 20 years after symptoms begin.
Adult form. This form is less common and typically starts after age 16. Signs progress slowly and may begin with behavior and psychiatric problems, drug and alcohol misuse, and issues with school and work. Psychotic symptoms such as delusions and hallucinations may occur. The course of this form varies, with periods of stable symptoms and periods of rapid decline in functioning. Adults may survive for several decades after initial symptoms.
