Recently, it was shown that the presence of TIMP3 variants (located on chromosome 22) are associated with BAV in TS– interestingly, individuals with TS who had both the deleterious TIMP3 risk variant and who were haploinsufficient for TIMP1, an Xp paralog of TIMP3, had a 20-fold increased risk for BAV, which provides convincing evidence of sensitization. The gene discussed is TIMP1; the disease is Timothy syndrome.