SAN FRANCISCO — In apparently the first decision of its kind in California, a state appeal court sided with plaintiffs Wednesday in a potential class action that blames a lender for misleading customers about the details of exotic mortgages.

The borrowers in the case accuse Irvine-based Home Loan Center Inc. of bamboozling them with misleading terms on option adjustable-rate mortgages, which featured an irresistible “teaser” rate that soon skyrocketed. The plaintiffs claim loss of equity in their homes and other damages.