Ans. A. HGPRTaseSlide 1 showing nibbling of lips and fingers; slide 2 showing bite marks on hand inflicted by self. Self-mutilation seen in Lesch Nyhan Syndrome; characteristic of the disease in children.Clinical signs and symptoms seen in Lesch Nyhan Syndrome:a. Biochemical: Hyperuricemia, can result ini. Gout (Joint pains)ii. Nephrolithiasis (abdominal pain, may be radiating in nature)iii. Tophib. Neurological:i. Mental Retardation (Poor performance in school)ii. Dystonia, variablec. Neuropsychiatric:i. Aggressive Behaviour (frequent fight, quarreling with siblings)ii. Self-Mutilation Tendency (associated with muscle loss; biting, chewing, etc.)d. Inheritance is XLR, enzyme absent is HGPRTase; in some patient, where the enzyme is not absent, but only diminished, have a less severe condition called Kelley Seegmiller Syndrome, where neurological and neuropsychiatric symptoms are either absent or very mild.