Kerstjens-Frederikse WS, Bongers EM, Roofthooft MT, Leter EM, Douwes JM, Van Dijk A, Vonk-Noordegraaf A, Dijk-Bos KK, Hoefsloot LH, Hoendermis ES, Gille JJ, Sikkema-Raddatz B, Hofstra RM, Berger RM., TBX4 mutations (small patella syndrome) are associated with childhood-onset pulmonary arterial hypertension, J Med Genet. This evidence concerns the gene TBX4 and coxopodopatellar syndrome.