Decreased Myocardial Taurine Levels and Hypertaurinuria in a Kindred with Mitral-Valve Prolapse and Congestive Cardiomyopathy

In a 46-member kindred with consanguineous ancestry, eight progeny in two generations had congestive cardiomyopathy and markedly elevated urinary taurine levels (range, 411 to 536 mg per gram of creatinine [normal ±S.D., 89±32]). Ten other family members had late or holosystolic mitral-valve prolapse, and elevated urinary taurine values (range, 215 to 265 mg). In two with mitral-valve prolapse, congestive cardiomyopathy eventually developed while the amounts of urinary taurine doubled. One member with mitral-valve prolapse died suddenly; histologic examination revealed myocardial fibrosis in the papillary muscles and myocardial taurine values of 16.9±3.0 μmol per gram of protein (normal ±S.E., 33.2±3.6). Four other family members with congestive cardiomyopathy had myocardial fibrosis at autopsy or biopsy and mean myocardial taurine levels of 9.2±2.2 μmol. We conclude that hypertaurinuria and depressed levels of taurine in the myocardium may be associated with one type of mitral-valve-prolapse syndrome and a rapidly progressive form of congestive cardiomyopathy. (N Engl J Med. 1981; 304:129–35.) ALTHOUGH mitral-valve prolapse and idiopathic congestive cardiomyopathy may occur together in any given family, 1 no common biochemical or genetic link has been established between these disorders. Numerous associations have been reported 2 3 4 5 6 7 however, mitral-valve prolapse usually occurs as an isolated phenomenon 8 and in most cases is idiopathic. 9 Likewise, congestive cardiomyopathy may result from several causes, but is also usually idiopathic. 10 There is evidence that mitral-valve prolapse, or at least one type of it, is transmitted through autosomal-dominant inheritance. 11 Idiopathic congestive cardiomyopathy may also be familial, but the pattern of inheritance is less clear. 12 We have studied a large, inbred kindred of . . .