每一千个男子中有一到二个具有女性核X染色质(染色质阳性).其性染色体异常的基本特征是至少存在一个额外的X染色体,通常核型是47,XXY.染色质阳性在胚胎发育早期就能识别,但在婴儿期和儿童期这种情况在临床上很少确诊.但是有证据表明婴儿的死亡率增高,在莫斯科,Bcchkov的研究发现,296个死男婴中有10个是染色 One to two out of every 1,000 men have a female nuclear X chromatin (chromatin positive). The basic feature of a sex chromosome abnormality is the presence of at least one additional X chromosome, usually a karyotype of 47,XXY. Chromatin is positive. Early embryonic development can be identified, but this condition is rarely diagnosed clinically during infancy and childhood. However, there is evidence that the infant’s mortality rate has increased. In Moscow, Bcchkov’s study found that 10 out of 296 dead male infants Are stained