A Turner syndrome woman with a ring X chromosome [45,X/46,X,r(X)(p22.3q27)] whose child also had a ring X chromosome

Abstract

To describe a woman with Turner syndrome with ring X chromosome mosaicism who had a child who possessed the same ring X chromosome. Polymorphisms of genes located on the X chromosome from genomic DNA of the mother, father, and the child were evaluated. The mother's karyotype was 45,X [48]/46,X,r(X)(p22.3q27) [2], and the child's karyotype was 45,X[33]/46,X,r(X)(p22.3q27) [17]. Polymerase chain reaction was used to amplify short tandem repeats from the loci of the hypoxanthine phosphoribosyltransferase gene and the androgen receptor gene. Alleles for both genes in the child originated from both parents in a heterozygous fashion. The alleles originating from the mother originated from the ring X chromosome. However, the amount of amplified DNA was less than that of a normal X chromosome. The ring X chromosome of the mother was most likely transmitted to the newborn. Thus, an ovum with the ring X chromosome can be fertile and can produce a viable zygote.