Clinical manifestations of CAH-X. Patients with CAH-X due to heterozygosity of a TNXA/TNXB chimera commonly have hypermobility of small joints, shown in Panel A, and large joints, shown in Panels B and C. Pes planus and piezogenic papules (arrow), shown in Panel D, are frequently observed. Approximately 25 percent of patients have a congenital cardiac defect. Panel E shows a quadricuspic aortic valve in a patient heterozygous for CAH-X CH-1 [73]. Hernias are most often observed in patients heterozygous for CAH-X CH-2, shown in Panel F, or biallelic for CAH-X. Hyperextensible skin is observed with CAH-X CH-2, and most severe with biallelic CAH-X, shown in Panels G and H. Panels C and F from reference [78]; with permission.