A couple is referred to the physician because their first three pregnancies have ended in spontaneous aboion. Chromosomal analysis reveals that the wife has two cell lines in her blood, one with a missing X chromosome (45,X) and the other normal (46,XX). Her chromosomal constitution can be described as?

The case described represents one of the more common chromosomal causes of reproductive failure, Turner mosaicism. Turner's syndrome represents a pattern of anomalies including sho stature, hea defects, and infeility. Turner's syndrome is often associated with a 45,X karyotype (monosomy X) in females, but mosaicism (i.e, two or more cell lines with different karyotypes in the same individual) is common. However, chimerism (i.e., two cell lines in an individual arising from different zygotes, such as fraternal twins who do not separate) is extremely rare. Trisomy refers to three copies of one chromosome, euploidy to a normal chromosome number, and mono ploidy to one set of chromosomes (haploidy in humans).