Nuzzo F, Zei G, Stefanini M, Colognola R, Santachiara A S, Lagomarsini P, Marinoni S, Salvaneschi L
Istituo di Genetica Biochimica ed Evoluzionistica, CNR, Pavia, Italy.
J Med Genet. 1990 Jan;27(1):21-5. doi: 10.1136/jmg.27.1.21.
The association of two rare hereditary disorders, trichothiodystrophy (TTD) and xeroderma pigmentosum (XP), was found in four patients from three families, apparently unrelated but living in the same geographical area. In order to test the hypothesis of a common ancestor, consanguinity within and among the families was checked using three different approaches: reconstruction of genealogical trees, typing of blood markers, and surname analysis. The results of the three types of analyses strengthen the hypothesis that, in at least two out of the three families, the genetic defect determining the TTD/XP phenotype is identical by descent, as a consequence of remote inbreeding. This implies that if two mutations are responsible for the two diseases they are at linked loci or affect the same gene.
在来自三个家庭的四名患者中发现了两种罕见的遗传性疾病——毛发硫营养不良（TTD）和着色性干皮病（XP）的关联，这三个家庭显然没有亲缘关系，但生活在同一地理区域。为了检验存在共同祖先的假设，使用了三种不同方法检查家庭内部和家庭之间的血缘关系：系谱树重建、血液标志物分型和姓氏分析。这三种分析类型的结果强化了这样一种假设，即由于远亲通婚，在这三个家庭中至少有两个家庭中，决定TTD/XP表型的遗传缺陷是同源的。这意味着，如果两种突变分别导致这两种疾病，那么它们位于连锁基因座上或影响同一个基因。
