The detection of a low level 45,X cell line during routine cytogenetic analysis in an adult female can be difficult to interpret. In the absence of recent information regarding loss of the X chromosome and ageing, we undertook a prospective study. A total of 19,650 cells from 655 females aged from birth to 80 years were screened cytogenetically. The frequency of X chromosome loss ranged from 0.07% at age <16 years to 7.3% at >65 years of age and showed a highly significant quadratic relationship between X chromosome loss and ageing (P ≤ 0.00001). We have produced a graphic representation that provides a minimum baseline age-related rate of X chromosome loss. This should assist diagnostic cytogenetics laboratories to determine the significance of 45,X cell lines detected in women of all ages. We also compared the frequency of 45,X cells in women referred with at least one spontaneous abortion with those referred for other reasons and found no significant difference. Thus, in our population, an excess of 45,X cells is not associated with pregnancy loss.

Women's NHS Foundation Trust, Liverpool , UK same directly transmitted 12.3-Mb interstitial deletion of 11q21q22.3 (GRCh37: 93,551,765-105,817,723) both had initial feeding difficulties and failure to thrive, speech delay, learning difficulties, and mild dysmorphism. Among 17 patients with overlapping deletions, developmental or speech delay, dysmorphism, hypotonia, intellectual disability or learning difficulties, short stature, and coloboma were each found in 2 or more. These results may provide the basis for a Abstract A phenotype is emerging for the proximal pair of G-dark bands in 11q (11q14.1 and q14.3) but not yet for the distal pair (11q22.1 and q22.3). A mother and daughter with the