Therefore,we sh ould us e the method to culture fragile chromosomes in addition to conventional chromoso me culfure to raise the diagnositic level of etiology of mental ret ardation.

• 结论本文建议临床在开展普通染色体培养方法的同时应开展脆性染色体培养方法，以提高精神发育迟滞的病因诊断水平。