Families

AP4B1-associated hereditary spastic paraplegia is a slowly-progressing inherited neurological disorders that generally present with global developmental delay, moderate to severe intellectual disability, impaired or absent speech, small head (microcephaly), seizures, and progressive motor symptoms. Low muscle tone (hypotonia) in infancy develops into high muscle tone (hypertonia), resulting in spasticity of the legs that leads to the inability to walk (non-ambulation) and wheelchair reliance. Spasticity may progress to the upper extremities, leading to the partial or total loss of use of all four limbs and torso (tetraplegia).