A rare karyotype of turner syndrome: 45.X/47.XXX

Abstract

Turner syndrome (TS)is a chromosomal disorder, which mostly results from a 45.XO karyotype and is characterized with short stature, gonadal dysgenesis, renal and cardiac abnormalities. The probability of spontaneous menarche in TS is 10%, while the probability of fertility is too low. The frequency of 45.X/47,XXX mosaicism in TS has been reported as 1% 4%. Cases with this karyo type were reported to have higher rates of spontaneous menarche and fertility with a lower incidence of short stature and renal abnormalities. A thirteen year old girl was admitted to our clinic with the complaints of decreased height velocity for the last two years and short stature compared to peers. On physical examination, her height was 135 cm (SD score 3.3) and weight was 32 kg (SD score 2.3) with breast development and pubic hair consistent with Tanner stage III. She also had an increased carrying angle of the elbow and low nuchal hairline. Remaining systemic physical examination was normal. Laboratory evaluation revealed normal complete blood count, renal, hepatic, and thyroid function test results. Bone age was consistent with 11 years. FSH was 5.99 mIU/mL, LH 2.94 mIU/mL, and E2 <20 pg/mL. The result of karyotype analysis was reported to be 45.X/47.XXX. She had no renal abnormality and echocardiogram revealed no pathological fnding except minimal mitral valve regurgitation. WISC R intelligence test was performed due to poor school skills and her IQ score was reported as 68. Recombinant human growth hormone treatment was started and at follow up, she had spontaneous menarche at the age of 13.5 years. With this report, it was aimed to emphasize i) the clinical features of this rare 45.X/47.XXX mosaicism and ii) the necessity of considering mosaic Turner syndrome in differential diagnosis and determining karyotype in all girls with short stature despite normal pubertal development.