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- Whom to screen for TS?
Turner syndrome should be suspected in any girl with short stature or delayed
puberty or having characteristic phenotypic abnormalities of TS, and a 30-cell
karyotyping should be performed in all these patients.- Why is 30-cell karyotype recommended for the diagnosis of TS?
Examination of at least 30 cells is required to detect 10 % mosaicism with 95 %
confidence interval. The rationale for selecting 10 % mosaicism is probably
based on the fact that approximately 10 % of aneuploidy (45, XO) is required to
express the phenotypic abnormalities of Turner syndrome in women with
45,XO/46,XX karyotype.- A 16-year-old girl presented with short stature and delayed puberty. On evalu-
ation she had the characteristic phenotype of Turner syndrome. Her karyotype
was 46,XX. How to proceed further?
The index patient has short stature, delayed puberty, and characteristic pheno-
typic features of Turner syndrome, with normal karyotype. Since the clinical
suspicion of TS is high, additional investigations are required. However, before
further investigations, it should be confirmed that 30 cells have been examined
on karyotyping to allow detection of mosaicism. Once it is ensured, tissue
karyotyping should be carried out from skin fibroblasts, hair follicles, or
gonadal tissue.- When to screen for Y chromosome material in patients with TS?
Patients with TS who have features of virilization or found to have marker
chromosomes on karyotyping should be screened for the presence of Y chro-
mosome material. DNA studies like polymerase chain reaction or FISH using a
Y centromeric probe are the recommended techniques for the detection of Y
chromosome material.- What are the implications of presence of Y chromosome fragments in patients
with TS?
Y chromosome or its fragments are present in approximately 5 % of patients
with TS, and its presence is associated with 12 % increased risk of developing
gonadoblastoma. Although gonadoblastoma is a benign tumor, it may trans-
form into malignant germ cell tumors including dysgerminoma in approxi-
mately 60 % of patients. Therefore, prophylactic laparoscopic gonadectomy is
recommended in patients with TS who have Y chromosome or its fragments.
Patients of TS with Y chromosome material may rarely have posterior labial
fusion or clitoromegaly at birth.8 Turner Syndrome