Ischiocoxopodopatellar syndrome with or without pulmonary arterial hypertension (TBX4 gene)
OMIM number: 147891
Comments closing date: 11/09/2026
Ischiocoxopodopatellar syndrome (ICPPS) is a rare inherited condition caused by alterations in
the TBX4 gene. The condition primarily affects the development of the pelvis, hips, knees and feet,
resulting in absent or underdeveloped kneecaps, abnormalities of the pelvis and hip joints, foot
deformities and varying degrees of joint pain or mobility problems. The severity is highly variable,
even between affected members of the same family. Some individuals have only mild skeletal
abnormalities, while others experience significant orthopaedic complications requiring surgery.
ICPPS is also associated with an increased risk of pulmonary arterial hypertension, a serious
condition in which the blood pressure within the arteries of the lungs becomes abnormally high,
potentially leading to heart failure and premature death if untreated.
