Johnson V P, Carpenter N J, Skorey P A
Department of Obstetrics/Gynecology, School of Medicine, University of South Dakota, Vermillion 57069.
Am J Med Genet. 1991 Feb-Mar;38(2-3):275-82. doi: 10.1002/ajmg.1320380222.
We report on a large kindred with 10 mentally retarded, fra(X) positive males and 2 normal transmitting males. Clinical findings include variable degrees of facial anomalies, macroorchidism, behavioral characteristics, and cognitive deficiencies. The affected grandsons were fra(X) positive while their obligate carrier mothers and transmitting grandfathers were fra(X) negative. DNA-restriction fragment length polymorphism (RFLP) linkage study was undertaken to find informative markers to identify heterozygotes or hemizygotes. The problems encountered in genetic counselling, by the absence of established criteria for diagnosis, are discussed.
我们报告了一个大家族，其中有10名精神发育迟滞、脆性X染色体（fra(X)）阳性男性和2名正常传递男性。临床发现包括不同程度的面部异常、巨睾症、行为特征和认知缺陷。受影响的孙子辈为fra(X)阳性，而他们必然携带致病基因的母亲和传递致病基因的祖父为fra(X)阴性。进行了DNA限制性片段长度多态性（RFLP）连锁研究，以寻找有信息价值的标记来识别杂合子或半合子。讨论了由于缺乏既定诊断标准在遗传咨询中遇到的问题。
