Turner Syndrome

Introduction

Turner syndrome has a prevalence of approximately 1 in 2500 female births. In 50% of cases the syndrome results from the complete loss of one X chromosome in a female (a 45,X karyotype). Prenatally, Turner syndrome may present as cystic hygroma or fetal hydrops detected by ultrasound scan. Postnatally, the most common feature of Turner syndrome is short stature, which becomes evident by about age 5. The other main features include extra folds of skin on the neck (webbed neck), a low hairline at the back of the neck, puffiness or swelling (lymphoedema) of the hands and feet, heart problems, skeletal abnormalities, and/or kidney problems. Many affected girls do not undergo puberty unless they are treated with the hormone oestrogen. The majority of individuals with Turner syndrome are infertile, however, small percentage of females with Turner syndrome retain normal ovarian function through young adulthood. The majority of females with Turner syndrome have normal intelligence. Some Turner syndrome patients may have a cell line containing Y chromosome material which is associated with an increased risk of gonadoblastoma. In the majority of cases Turner syndrome arises as a sporadic event. Variant Turner syndrome can also occur when one normal X chromosome and one structurally abnormal X chromosome are present. Individuals with variant Turner syndrome may present with a milder phenotype than those females where a complete X chromosome is missing. Turner syndrome can also appear in a mosaic form, where normal cells are also present in the individual (a 45,X/46,XX karyotype). These individuals may exhibit a milder phenotype, which is dependent on the extent and tissue distribution of the normal cell line. One of the critical regions for the Turner syndrome phenotype, specifically short stature and skeletal abnormalities, is loss of the SHOX gene at Xp22.33.

Referral information

We accept prenatal samples (amniotic fluid and chorionic villus biopsies) from pregnancies where ultrasound scanning has shown a nuchal translucency measurement of greater than 3.5mm in the first trimester or 6mm in the second trimester, cystic hygroma or fetal hydrops. We accept postnatal blood samples from females with appropriate clinical features for a diagnosis of Turner syndrome. Tissue samples from pregnancy losses are also accepted.

Price & reporting times

NHS referrals to this service are paid for where there is an existing specialist commissioning contract for genetic testing. In other cases please contact the lab for prices.

Test Price (£ ex VAT) TRT *
QF-PCR POA 3 cd
Prenatal or neonatal microarray analysis POA 14 cd
G-banded neonatal chromosome analysis POA 10 cd
G-banded prenatal chromosome analysis POA 14 cd

Test validation & quality assurance - information for users

The QF-PCR test is for detection of monosomy X only and will not detect mosaicism or structural rearrangements. Rarely, testing may be uninformative or fail to give a result. Microarray analysis will not detected balanced rearrangements and may not detect mosaicism. Maternal cell contamination is excluded for prenatal samples prior to microarray testing by analysis of a maternal blood sample. This laboratory participates in the CEQAS quality assessment scheme for this test.

Referral guidelines

Please see our referral guidelines for more information.

y