XYY constitution in prepubertal child.

Medical Memoranda BRJoII of yG, yA, yM, and yD, but the interstitial tissue was positive for yG. COMMENT At first the diagnosis was thought to be gastric carcinoma with clear-cut dermatomyositis, but operative histology and later post-mortem examination revealed undoubted plasmacytoma, with involvement of the bone marrow. This diagnosis had not been suggested by the clinical findings or by the investigations. There had never been a raised E.S.R. or proteinuria, and serum proteins were normal; radiographs of the spine failed to show any deposits. Extraosseous lesions in plasma cell myeloma are uncommon (Edwards and Zawadski, 1967) and skin lesions are distinctly rare in such cases involvement of the bone marrow is most unusual. The concentration of L paraprotein in the tumour was low, and the amount in the urine was small for the extent of the tumour. The excess of polyclonal yG-globulin found in the tumour (though not in the cytoplasm of the contained plasma cells, which had Bence Jones only) suggests an immune reaction. Reaction to an antigen common to the tumour, the skin, and muscle could be responsible for the clinical picture of dermatomyositis. It is suggested that when patients with dermatomyositis fail to improve when given large doses of steroids a careful search should be made for an underlying neoplasm, and that this should include studies for M-band and Bence Jones protein. A considerable body of information now exists with respect to the physical and psychological concomitants of the XYY chromosome constitution in adult males. We believe this report is the first to be made of the findings in a prepubertal boy of normal intelligence with this karyotype. The patient, a boy aged 8 years 7 months, was 11 days postmature and weighed 7 lb. 6j oz. (3,365 g.) at birth. He was the firstborn wanted child of a mother aged 23 and father aged 26. Pregnancy, birth, milestones, and early development were unremarkable. He walked unaided and was talking at 18 months, and was clean and dry by two years. He was referred to one of us (J. C.) when 4-i years old because he was unmanageable at home, destructive, mischievous, and defiant. He would smash his toys, rip the curtains, set fire to the room in his mother's absence, and kick the cat and his 8-month-old brother. He was over-adventuresome and without fear; he would climb high ladders in buildings, climb out on to window …