This paper is a review of clinical experiences providing developmental therapy services for three boys diagnosed with paediatric neurotransmitter disease. The clinical presentation of paediatric neurotransmitter diseases might parallel other diagnostic characteristics seen in a typical paediatric therapy clinic (i.e. hypotonia, motor and cognitive delays, coordination, expressive speech, and ocular motor difficulties.) From the clinical perspective of the author, sensory integrative function is but one aspect of a thorough evaluation and treatment plan for all patients. The manifestations of sensory integration dysfunction (SID), also known as sensory processing dysfunction (SPD), can occur alone or be concurrent with a variety of known medical, behavioural and neurological diagnoses. These manifestations of SPD can include, but are not limited to: hypotonia, hyperactivity, irritability, distractibility, attention difficulties, learning difficulties, clumsiness and incoordination, instability, poor motor skills, social-emotional difficulties, and behavioural problems. This paper summarizes the theory and practice applications of sensory integration. The author discusses clinical experiences providing occupational therapy services utilizing sensory integration methods and strategies with clients who were eventually diagnosed with SSADH deficiency.