Molecular and cytogenetic studies of X inactivation in a patient with 46,X,del(X)(q22)

We report on a phenotypically normal girl with a deletion of the distal long arm of one X chromosome at Xq22, and spontaneous pubertal development including menarche. This suggests that the distal long arm of the X chromosome is not crucial for ovarian development. Cytogenetic and polymerase chain reaction (PCR) amplification methods both showed preferential inactivation of the deleted X chromosome. The PCR-based assay has the additional advantage of identifying the paternal origin of the deleted X chromosome.