Turner syndrome

Madelung

deformity • Turner's syndrome - hand - Ganzer Fall bei Radiopaedia

Gaillard, F. Turner's syndrome - hand. Case study, Radiopaedia.org. (accessed on 02 Nov 2022) https://doi.org/10.53347/rID-6273 • CC by-nc-sa 3.0 (modified)

Positive

metacarpal sign • Turner syndrome - hand - Ganzer Fall bei Radiopaedia

Byrne A, Turner syndrome - hand. Case study, Radiopaedia.org (Accessed on 28 Nov 2022) https://doi.org/10.53347/rID-7583 • CC by-nc-sa 3.0 (modified)

Turner

syndrome • Short metacarpals in Turner syndrome - Ganzer Fall bei Radiopaedia

Radswiki T, Short metacarpals in Turner syndrome. Case study, Radiopaedia.org (Accessed on 28 Nov 2022) https://doi.org/10.53347/rID-12045 • CC by-nc-sa 3.0 (modified)

Turner

syndrome • Short fourth and fifth metacarpals - Turner syndrome - Ganzer Fall bei Radiopaedia

Gaillard F, Short fourth and fifth metacarpals - Turner syndrome. Case study, Radiopaedia.org (Accessed on 28 Nov 2022) https://doi.org/10.53347/rID-8742 • CC by-nc-sa 3.0 (modified)

Turner

syndrome • Cystic hygroma (Turner's syndrome) - Ganzer Fall bei Radiopaedia

Jha P, Cystic hygroma (Turner's syndrome). Case study, Radiopaedia.org (Accessed on 28 Nov 2022) https://doi.org/10.53347/rID-16607 • CC by-nc-sa 3.0 (modified)

Radiopaedia • CC-by-nc-sa 3.0 • de

Turner syndrome, also known as 45XO or 45X, is the most common of the sex chromosome abnormalities in females.

Epidemiology

The incidence is estimated at 1:2000-5000 of live births, although the in utero rate is much higher (1-2% of conceptions) due to a significant proportion of fetuses with 45X aborting by the 2trimester.

Clinical presentation

In adults, it is one of the most important causes of primary amenorrhea and accounts for approximately one-third of such cases.

Pathology

Genetics

Turner syndrome is classically characterized by the absence of one X chromosome copy (45 XO), with the missing chromosome most frequently (two-thirds) being the paternal one. Most cases occur as a sporadic event.

However, the classic genetic change is not present in all cases. Three main subtypes include:

complete monosomy (45XO): ~60%
- even though it is relatively common, almost all 45 XO fetuses will spontaneously abort, with 70% lost between 16 weeks and term
partial monosomy (structurally-altered X chromosome): ~15%
mosaicism (XO and another sex karyotype): ~30%

Unlike the common trisomies, there is no association with maternal age.

Markers

serum alpha-fetoprotein (AFP): decreased
beta HCG
- elevated if hydrops present
- decreased if no hydrops
serum inhibin
- elevated if hydrops present
- absent if hydrops absent

Associations

hypertension
glucose intolerance
inflammatory bowel disease
hypothyroidism: due to the formation of thyroid antibodies (most commonly Hashimoto thyroiditis)
gonadal dysgenesis / ovarian dysgenesis

Complications

In utero complications include:

development of hydrops fetalis: usually from fluid overload secondary to lymphatic failure

Radiographic features

Antenatal ultrasound

cystic hygroma: may appear septated; one of the most typical features of Turner syndrome
increased nuchal thickness
increased nuchal translucency
coarctation of the aorta: 15-20%
bicuspid aortic valve
horseshoe kidney / pelvic kidney
mild IUGR
features related to complicating hydrops fetalis
short fetal limbs

Postpartum-to-adulthood features

Musculoskeletal

scoliosis
short 4metacarpal: positive metacarpal sign
narrowing scapholunate angle: positive carpal sign
abnormal medial femoral condyle
decreased carpal angle: Madelung deformity
short stature
webbed neck
valgus deformity of the elbow: increased carrying angle (cubitus valgus)

Pelvic ultrasound

streaky uterus
streak ovary

Gastrointestinal

pyloric stenosis

Treatment and prognosis

Overall prognosis very variable is dependent on associated anomalies. While the vast majority of fetuses are aborted in the second trimester, some may have a long life expectancy. Cases with mosaicism do much better. Mental development is unaffected.