Turner syndrome (TS) is a chromosomal disorder characterized by complete or partial loss of one X chromosome. One structural variant, isochromosome Xq [46,X,i(Xq)], results in duplication of the long arm and loss of the short arm of the X chromosome (Xp), which contains genes essential for normal ovarian development and function. This chromosomal imbalance leads to accelerated germ cell apoptosis and subsequent ovarian dysfunction. In this case, a 33-year-old woman with chronic anovulation and uterine hypoplasia was diagnosed with 46,X,i(Xq) karyotype without evidence of mosaicism. A 33-year-old woman with a history of irregular menstruation since adolescence was referred for evaluation of uterine hypoplasia and chronic anovulation. Clinical findings included short stature, but no webbed neck or congenital heart defects, making this an atypical presentation of Turner syndrome. Transvaginal ultrasound revealed a small uterus and bilateral streak ovaries. Hormonal evaluation showed elevated FSH levels consistent with hypergonadotropic hypogonadism. Diagnostic laparoscopy confirmed bilateral streak ovaries with normal appearing uterus and fallopian tubes. Chromosomal analysis using G-banding revealed a 46,X,i(Xq) karyotype, indicating an isochromosome Xq abnormality, a recognized variant of Turner syndrome. This genetic alteration explains her ovarian dysfunction and infertility, highlighting the importance of chromosomal evaluation in cases of primary ovarian insufficiency. This case highlights a structurally abnormal but nonmosaic 46,X,i(Xq) karyotype variant of Turner syndrome presenting primarily with ovarian insufficiency. Despite the absence of classic phenotypic features such as webbed neck or congenital heart defects, a high index of suspicion led to the correct diagnosis. This case underscores the need to consider Turner syndrome variants in women with unexplained ovarian insufficiency, even in the absence of overt clinical stigmata, to guide appropriate genetic counseling and fertility planning.

Xq duplication is a rare condition with a very variable phenotype, which could mimic other genetic syndromes involving the long arm of chromosome X. Sometimes short stature and diminished ovarian reserve (DOR) may be present. Treatments with rGH (Recombinant growth Hormon) or with fertility preservation strategies have not been previously described. We present the case of a female with a novel de novo Xq partial duplication (karyotype: 46,Xder(X)(qter→q21.31::pter→qter) confirmed by array-CGH analysis. She presented with short stature, Nonverbal Learning Disability, developmental delay during childhood, severe scoliosis, spontaneous onset of menarche and irregular menstrual cycles. AMH (Anti-Müllerian Hormone) allowed detection of a preserved but severely diminished ovarian reserve with a POI (Premature Ovarian insufficiency) onset risk. She was effectively subjected to fertility preservation strategies and rGH therapy. We also reviewed other published cases with Xq duplication, reporting the main clinics characteristics and any adopted treatment. rGH treatment and cryopreservation in a multidisciplinary approach are good therapeutic strategies for Xq duplication syndrome with short stature and premature ovarian failure.

Chromosome 18p deletion syndrome is a disease caused by the complete or partial deletion of the short arm of chromosome 18, there were few cases reported about the prenatal diagnosis of 18p deletion syndrome. Noninvasive prenatal testing (NIPT) is widely used in the screening of common fetal chromosome aneuploidy. However, the segmental deletions and duplications should also be concerned. Except that some cases had increased nuchal translucency or holoprosencephaly, most of the fetal phenotype of 18p deletion syndrome may not be evident during the pregnancy, 18p deletion syndrome was always accidentally discovered during the prenatal examination. In our case, we found a pure partial monosomy 18p deletion during the confirmation of the result of NIPT by copy number variation sequencing (CNV-Seq). The result of NIPT suggested that there was a partial or complete deletion of X chromosome. The amniotic fluid karyotype was normal, but result of CNV-Seq indicated a 7.56 Mb deletion on the short arm of chromosome 18 but not in the couple, which means the deletion was de novo deletion. Finally, the parents chose to terminate the pregnancy. To our knowledge, this is the first case of prenatal diagnosis of 18p deletion syndrome following NIPT.NIPT combined with ultrasound may be a relatively efficient method to screen chromosome microdeletions especially for the 18p deletion syndrome.

Discordance between clinical phenotype and genotype has multiple causes, including mosaicism. Phenotypes can be modified due to tissue distribution, or the presence of multiple abnormal cell lines with different genomic contributions. We have studied a 20-month-old female whose main phenotypes were failure to thrive, developmental delay, and patchy skin pigmentation. Initial chromosome and SNP microarray analysis of her blood revealed a non-mosaic ∼24 Mb duplication of 15q25.1q26.3 resulting from the unbalanced translocation of terminal 15q to the short arm of chromosome 15. The most common feature associated with distal trisomy 15q is prenatal and postnatal overgrowth, which was not consistent with this patient's phenotype. The phenotypic discordance, in combination with the patchy skin pigmentation, suggested the presence of mosaicism. Further analysis of skin biopsies from both hyper- and hypopigmented regions confirmed the presence of an additional cell line with the short arm of chromosome X deleted and replaced by the entire long arm of chromosome 15. The Xp deletion, consistent with a variant Turner Syndrome diagnosis, better explained the patient's phenotype. Parental studies revealed that the alterations in both cell lines were de novo and the duplicated distal 15q and the deleted Xp were from different parental origins, suggesting a mitotic event. The possible mechanism for the occurrence of two mutually exclusive structural rearrangements with both involving the long arm of chromosome 15 is discussed.