Bone I, Johnson R H, Ferguson-Smith M A
J Neurol Neurosurg Psychiatry. 1976 Nov;39(11):1129-33. doi: 10.1136/jnnp.39.11.1129.
Three patients who suffer from spastic paraplegia are described who belong to two generations in one family. One of the patients, who has had symptoms and signs for at least 10 years, has a monozygous twin who is unaffected. Using blood groups and chromosomal polymorphisms, the probability of monozygosity is estimated to be 0.99986. The observation of nonpenetrance in familial spastic paraplegia suggests that environmental factors may be involved in provocation and emphasises the need for careful genetic counselling in this and related diseases.
本文描述了一个家族中两代人患痉挛性截瘫的三名患者。其中一名患者出现症状和体征至少已有10年，其同卵双胞胎未受影响。利用血型和染色体多态性，估计同卵双生的概率为0.99986。家族性痉挛性截瘫中出现的非外显现象表明，环境因素可能参与了该病的诱发，这突出了对此病及相关疾病进行仔细遗传咨询的必要性。
