不完全外显:40 个携带者中 32 人患病(f = 80%) 40 个基因型携带者中 32 人表现表型 → 外显率 f = 32/40 = 80%,外显不全率 = 20%(部分携带者终生不表现性状,如豚鼠多指或 BRCA1 的情形)。在 32 个患病者中,表现度分布:重度 8 人(25%)、轻度 12 人(37.5%)、中度余数 12 人(37.5%)。{"result":"Penetrance f = 32/40 = 80% (nonpenetrance 20%). Expressivity among 32 affected: severe 25%, moderate 37.5%, mild 37.5%.","metadata":{"input":{"genotypeCarriers":40,"affectedCarriers":32},"result":{"penetrance":0.8,"nonPenetrance":0.2,"expressivity":{"severe":0.25,"moderate":0.375,"mild":0.375}}}}
50 个 1 型神经纤维瘤病样基因型携带者全部患病:外显率 f = 100%、无外显不全,但表现度仍然可变——重度 5 人(10%)、轻度 30 人(60%)、中度余数 15 人(30%)。这说明外显率(全或无)与表现度(程度)是相互独立的概念。{"result":"Penetrance f = 50/50 = 100% (complete). Expressivity among 50 affected: severe 10%, moderate 30%, mild 60%.","metadata":{"input":{"genotypeCarriers":50,"affectedCarriers":50},"result":{"penetrance":1,"nonPenetrance":0,"expressivity":{"severe":0.1,"moderate":0.3,"mild":0.6}}}}