This is the first reported patient in whom the genes suspected to cause BS and/or GS were examined, and several mutations were identified in CLCNKB, CASR, SLC12A3, SLC12A1, and SLC26A3. These findings suggest that BS and/or GS are hereditary salt-losing tubulopathies caused by not just one mutation, but several overlapped mutations. Here, CASR is linked to Bloom syndrome.