[Genetic analysis of Turner syndrome: 89 cases in Tunisia]

Patient with Mosaic Turner Syndrome and a Derivative X Chromosome with a Variant Triple X Diagnosis in Fetus: A Case Report

Although Turner syndrome is most often sporadic, multigenerational recurrence has been reported more often in the offspring of women with mosaic or variant forms of Turner syndrome. We present a case in which natural conception in a woman with identified 45,X/46,XX mosaicism resulted in a fetus with a gain of a derivative X chromosome. The unexpected fetal finding prompted further cytogenetic evaluation of the patient and subsequent identification of an additional cell line with the same derivative X chromosome, not observed in the initial study. To our knowledge, this is the first case in which further investigation of an abnormal noninvasive prenatal screen resulted in the identification of both maternal and fetal sex chromosome abnormality. We discuss the discordant finding, similar cases, and potential phenotype with respect to skewed X inactivation. We also highlight the use of multiple testing methodologies to characterize the serendipitous identification of a derivative X chromosome.

Genetics and genomic medicine in Tunisia

Genetics and genomic medicine in Tunisia.

Nationwide Study of Turner Syndrome in Ukrainian Children: Prevalence, Genetic Variants and Phenotypic Features

Objective

We aimed to investigate the prevalence of Turner syndrome (TS) in the Ukrainian population, the frequency of karyotype variants, the age of children at diagnosis, the degree of short stature and phenotypic features in TS girls.

Methods

A retrospective analysis was made in 538 TS girls aged 0.11-18.2 years within the time period of 2005-2015 with detailed examination of 150 patients.

Results

The prevalence of TS in Ukraine is 77.5 in 100.000 live female births. The average age at diagnosis is 9.33±4.93 years. The relative proportions of karyotypic abnormalities found were: 45,X (59.3%); mosaicism 45,X/46,XX (22.9%); and structural abnormalities in chromosome X (17.8%). The most frequently encountered findings were growth delay (98.8%), shortening of the 4th and 5th metacarpal bones (74.6%), abnormal nails (73.3%), broad chest (60.7%), short neck (58.6%), hypertelorism of nipples (51.4%), malformations of the cardiovascular (19.6%) and urinary systems (13.8%) and pathology related to vision (20.1%) and hearing (22.0%).

Conclusion

In the Ukrainian population, the highest proportion of patients with TS had a karyotype 45,X. TS was accompanied by a lower frequency of malformations of internal organs compared to other countries.

Turner Syndrome: A Unique Mosaic Case with 45,X/47,XX,+21/46,XX Cell Lines

We report an extremely rare case of Turner syndrome mosaicism in a 30-year-old woman. At least 100 metaphases were observed and analyzed through GTG banding with over 550 band resolutions observed. G-banded chromosome analysis revealed a mosaic female karyotype involving 3 different cell lines. One cell line (90% of the analyzed metaphases) presented monosomy X, while 6% of the cells showed trisomy of chromosome 21 and 4% of the cells exhibited a normal female karyotype. Fluorescence in situ hybridization with a locus-specific probe for trisomy 21 and CEP X for monosomy X substantiated the results obtained from karyotyping. Our patient had 2 natural pregnancies, both of which produced children with Down syndrome. In our patient, as is the case with other women with infertility, the necessary routine is cytogenetic analysis (together with genetic counseling). The same analysis can be helpful in implementing assisted reproductive techniques.

Features of Turner syndrome among a group of Cameroonian patients

OBJECTIVE

To describe the features of Turner syndrome among a group of Cameroonian patients.

METHODS

A descriptive cross-sectional study was conducted among patients with amenorrhea and/or short stature who attended the genetic unit of Yaoundé Gynecology, Obstetrics and Pediatric Hospital (Yaoundé, Cameroon) for a specialist consultation between July 1, 2007, and December 31, 2008. Sociodemographic, clinical, and cytogenetic data were collected.

RESULTS

Turner syndrome was confirmed among 11 of the 14 participants (seven had monosomy of the X chromosome; four had mosaicism involving a structural abnormality of the second X chromosome). The mean age at diagnosis was 18.4±2.8years. The reasons for consultation were delayed puberty (n=10) and short stature (n=1). Nine patients had a short neck, nine had a forearm carrying-angle deformity, eight had a low hairline, and two had a webbed neck. Abdominal ultrasonography identified a horseshoe kidney in two patients and a rudimentary uterus in nine patients. None of the patients displayed cardiac abnormalities. Hypergonadotropic hypogonadism was reported among five patients. Eight patients did not receive hormonal treatment owing to advanced bone age or economic reasons.

CONCLUSION

Late diagnosis and variable phenotypic expression were key features of Cameroonian patients with Turner syndrome.

Markers of ovarian reserve in young girls with Turner's syndrome

We describe a preliminary report identifying markers of ovarian reserve to identify candidates for ovarian cryopreservation. Among 14 patients with Turner's syndrome, those with a poor probability of fertility had a significantly higher FSH, lower inhibin A, and lower AMH compared with those with a fair probability of fertility.