Gokce et al. (2001) reported a 22-year-old female with features of Marfan syndrome (154700) combined with abdominal situs inversus, dextrocardia, and polysplenia. Her cardiac disease included calcified right coronary aortic cusp, a discrete subaortic membrane with mild aortic ... Gokce et al. (2001) reported a 22-year-old female with features of Marfan syndrome (154700) combined with abdominal situs inversus, dextrocardia, and polysplenia. Her cardiac disease included calcified right coronary aortic cusp, a discrete subaortic membrane with mild aortic regurgitation, and minimal mitral value prolapse and insufficiency. She was tall and had scoliosis, arachnodactyly, and subluxation of the right lens. Gokce et al. (2001) found no previously reported case of Marfan syndrome combined with complete situs inversus or discrete subaortic stenosis. Kosaki et al. (2004) described similar features in 2 unrelated children, a 14-year-old Japanese male and an 11-year-old Caucasian female, who were both born to nonconsanguineous parents. The boy's parents were phenotypically normal; both of the girl's parents were tall and had mitral valve prolapse without other Marfan syndrome stigmata. Both children had dextrocardia and abdominal situs inversus, obstructive sleep apnea, severe scoliosis, and normal chromosome analyses. Physical examinations in both showed signs of Marfan syndrome: pectus carinatum, reduced upper to lower body segment ratio, finger hyperextensibility, and positive wrist sign. The male had valvular pulmonary stenosis requiring valvectomy at 3 years, an azygous connection, arachnodactyly, and myopia without lens subluxation; the female was tall and had patent ductus ligation neonatally, dilatation of the aortic and pulmonary roots, generalized joint hyperextensibility, persistent muscle weakness, and increasing oxygen dependence with a fatal arrhythmia at age 15 years. An extensive evaluation of the female found a nonsignificant polymorphism of COL1A2 (120160), normal fibrillin studies by pulse chase analysis of fibrillin-1 (134797) cellular metabolism, and reduced numbers of muscle mitochondria with normal biochemical measures of mitochondrial function. Kosaki et al. (2004) concluded that these children and the patient reported by Gokce et al. (2001) had a recognizable, distinct syndrome as none fulfilled the Ghent diagnostic criteria for Marfan syndrome and no fibrillin or collagen abnormalities were found. Kosaki et al. (2004) suggested a TGF-beta (TGFB1; 190180) signaling pathway defect as the underlying etiology.