SLC6A8 and hyperinsulinemic hypoglycemia, familial, 4: Furthermore, considering the physiological impairments such as intellectual disability, seizures, muscle weakness and gastrointestinal issues that symptomatically characterize genetic diseases of creatine deficiency (such as arginine: glycine amidinotransferase deficiency, guanidinoacetate methyltransferase deficiency, and creatine transporter deficiency); it is clear that creatine plays a vital role in bioenergetics, metabolism and overall cellular health.