Introduction: Turner syndrome (TS) is one of the most common chromosomic disorders characterized by partial or complete lack of one of X chromosomes. It presents variable phenotypic spectrum. Isochromosome of long arm (iXq10) is the third most frequent karyotype and could be in mosaicism in 10-15% of TS. The phenotypic manifestation are similar than girls 45X. It is described a higher incidence of thyroid autoimmunity (even though is currently under discussion) and of diabetes mellitus. Congenital heart malformations and premature ovarian failure are less frequent. One third of the girls with TS have spontaneous puberal development, more often in those with mosaicism and some structural anomalies. Spontaneous pregnancies are rare (35%).
Case report: We describe a family with vertical transmission of TS carrying non-mosaic isochromosome X (karyotype 46Xi[Xq]), which involves 4 women of two generations. The index case is a girl of 8.7 years old who was referred at 2.9 years old because of horseshoe kidney and phenotypic features compatible with TS. She was 92.8 cm tall (−1.23 SDS) and has high-arched palate, lower implanted ears, cubitus valgus and broad chest. She has been on growth hormone treatment since she was 4.3 years old. Additionally, she has mild intellectual disability (IQ 76). Her mother has short stature, with a height of 135 cm (−4.6 SDS). She had three full-term pregnancies and two spontaneous abortions. Because of her short stature a karyotype was performed, with the same results as her daughter. She has cubitus valgus, Madelung deformity and altered sitting height. The two sisters had same karyotype, the older one with spontaneous puberty, cubitus valgus, Madelung deformity, altered sitting height, and mild intellectual disability (IQ 78), with thyroid autoimmunity; and the younger one with cubitus valgus, broad chest and more severe intellectual disability.
Conclusion: Despite the low frequency of spontaneous pregnancies in patients with TS and even more infrequent TS transmission, when ovarian function is preserved, it is possible to transmit TS to next generations. Two of the four exposed cases developed spontaneous puberty, and the mother had five pregnancies, two full term. The phenotypic expression was variable despite having the same karyotype. The index case is the only that does not have marked corporal disproportion and we think this could be related with growth hormone treatment. In this family, we think that it is important to have genetic counseling, as it is possible to continue with TS transmission.
27 - 29 Sep 2018
European Society for Paediatric Endocrinology