Mutations in MFF may cause the following health conditions:
Central Nervous System
- Delayed psychomotor development (delay in acquiring motor and cognitive skills)
- Developmental regression (loss of previously acquired skills)
- Poor head and trunk control
- Absent speech
- Spasticity (stiffness or rightness of the muscles that can interfere with normal movement)
- Hyperreflexia (overactive or overresponsive reflexes)
- Seizures
- Abnormalities detected on EEG
- Abnormalities detected on MRI (especially common are abnormalities in the basal ganglia, a structure in the brain responsible for motor control and motor learning)
- Peripheral neuropathy (impairment of the nerves that carry signals to and from the brain and spinal cord to and from the rest of the body)
- Severely reduced muscle tone
Head and Neck
- Abnormally small head
- Visual impairment
Other
- Difficulty swallowing
- Abnormal laboratory findings, including increased lactate levels