A PEDIGREE OF MENTAL DEFECT SHOWING SEX-LINKAGE.

Abstract

THE following history of imbecility in eleven males of two generations was brought to our notice some years ago when a child aged.eighteen months, now indicated as V 54 on the adjoining pedigree chart, was brought to the outpatient department at the National Hospital by his mother who suspected that he was showing the signs of mental deficiency which she had already seen develop in some of the sons of her sisters; she was further aware of the condition in her cousins IV 13 and 14. The mother of the patient, IV 22, was intelligent and was much concerned about the family history; she provided at that time complete information regarding her own branch of the family and obtained the collaboration of her aunt, III 1, in working out the extended pedigree, including the three defective brothers V 16, 18, and 19. At this time one of us (J.P.M.) visited many of the descendants of III 4; he noted the undoubted intelligence of the seven daughters of III 4 and examined their defective sons in institutions or in their homes. More recently we have been able to get in touch with some of the descendants of III 2 and to see the three imbecile sons of IV 3. This side of the pedigree has been much extended since the original history was given by III 1, and to some extent modified. Our information was provided by IV 3 and 4, but they did not welcome inquiry and discouraged our attempt to see the only other living member of the sibship IV 1-11, or to call upon V 13. IV 3 was uncertain about some details regarding the sex and number of her nieces and nephews and we did not feel assured that she would know if, for example, IV 2, or IV 9 had had defective sons or grandsons. Two of the twins of IV 2 had died in infancy, but IV 3 did not know whether they had been boys or girls. It is illustrative of the secretive-ness of this branch of the family that at the time of the earlier pedigree III 1 was unaware that she had any grandchildren through her daughter IV 2, or that her son IV 1 had more than one child. IV 3 was fiercely protective in her attitude to her imbecile sons and resentful that, when found as small boys wandering in …