Endocrine Abstracts

Case History: A 16 yr old patient presented to us concerned about her short statue. Her father and mother were at the 9th centile and her sister was at the 25th centile in adult life. She was otherwise well having gone through a normal puberty in her early teens and was currently on the oral contraceptive pill having regular periods. On examination she did display some features of Turner’s syndrome; short stature, short neck and cubitus valgus deformity. Cytogenetic analysis revealed a karyotype 45, X [18]/47, XXX [12]. The report concluded that there was evidence of this abnormal female mosaic karyotype with 60% of cells having a chromosome count of 45 with only one X chromosome and 40% of cells having a chromosome count of 47 with three X chromosomes.

Discussion: This is a rare mosaicism. The more common 45 X/46, XX generally results in full Turner syndrome. It is recognised that the clinical phenotype can sometimes be mitigated by the presence of the 46, XX cell line, with the exact phenotype depending on the ratio of 45, X cells to 47, XXX cells in the developing organs. It has been noted that cell lines different to 45 X may be necessary for foetal survival. Mosaics can also involve Y chromosomes.

Literature search shows 12 patients with similar Turner mosaicism has had 16 healthy pregnancies. Within this case report we discuss how such mosaics occur and review the natural history of Turner mosaic patients reported in the literature.