家族性心房中隔欠損症の二家系—単独家系と他疾患合併の家系

Secundum atrial septal defect in two families

　家族性二次口心房中隔欠損症（ASD）の二家系を報告する。一家系では，発端者の31歳男性とその母親にPR延長を伴わない二次口ASDが認められた。兄にもASDがあり，祖母も先天性心疾患が疑われた。この家系はASD単独家系と推測され，優性遺伝の可能性が考えられた。他の一家系では，同胞5人中発端者の16歳女性と18歳男性に二次口ASDが認められ，長姉と次兄には不明の先天性心疾患，長兄にはファロー四徴症があった。この5人中4人は知能障害を伴っていた。両親は健在であるが，いとこ結婚であった。この家系は他の先天性心疾患および知能障害を伴うASD家系で，常染色体劣性遺伝の可能性が考えられた。

Two families having secundum atrial septal defect (ASD) were reported. In one family, a 31-year-old male and his 60-year-old mother had secundum ASD without PR prolongation. His 38-year-old brother was diagnosed as having ASD. His grandmother, who had died at the age of 51, was suspected of having congenital heart disease. From early child-hood she was noticed to have heart murmur. It was suspected that this was a case of familial ASD without PR prolongation, because it was consistent with the dominant trait of the defect. In the other family, a 16-year-old female had secundum ASD and her 18-year-old brother was also suspected of having ASD. Her 25-year-old brother had been operated on for tetralogy of Fallot, and her sister had died of an unknown congenital heart disease. All of these family members had mental retardation. Her 22-year-old brother was suspected of having a con-genital heart disease, because of heart murmur from his early childhood. The parents, who were blood relations (cousins), had neither heart disease nor mental retardation. The children of this family were considered to be cases of congenited heart disease with ASD, associated with mental retardation. It was also suspected that the cause of the defect was a deleterious autosomal recessive gene.