Tests
1st tests to order
karyotype
Test
Abnormalities include nonmosaic 45,X; mosaic 45,X (proportion of cells with a normal chromosome constitution); and fragmented X or Y (Xp deletions, isoXq chromosomes, Xq deletions, and ring X or Y chromosomes with substantial interstitial deletions).
A minimum of 20 cells need to be scored for chromosome number. The analysis is complete if mosaicism is confirmed. If one cell with a sex chromosome loss, gain or rearrangement is observed within the first 20 cells analyzed, a minimum of 10 additional cells should be evaluated.
The test identifies 10% mosaicism or greater with 95% confidence.[3][26][27]
In patients with a strong suspicion of the diagnosis, if the test proves <10% of cells to be abnormal, more metaphases need to be counted along with fluorescence in situ hybridization (FISH), or other cell types may be analyzed with interphase FISH, in consultation with a geneticist/cytogeneticist.[28]
It is recommended that the test should be repeated in the following circumstances: infants diagnosed prenatally should have a postpartum karyotype to confirm the diagnosis; individuals diagnosed by buccal swab only; individuals with a karyotype performed in the distant past; the original report is not available for review. If none of these apply, do not order a duplicate genetic test unless there is uncertainty about the existing result.[25]
Result
at least 10% of the cells with a complete or partial loss of a sex chromosome
Tests to consider
audiology testing
Test
Should be performed at the time of diagnosis and reassessed every 3-5 years.
Result
may be abnormal
ophthalmological examination
Test
Girls with Turner Syndrome have an epicanthal fold (upper eyelid fold that covers inner corner of eye) and hypertelorism (increased distance between eyes). A comprehensive ophthalmological examination should be performed between ages 12 and 18 months or at the time of diagnosis, if at an older age, to evaluate for refractive errors and other vision issues.
Result
Strabismus, amblyopia, hyperopia and myopia, ptosis and color blindness have all been reported
bone age
Test
Radiography is the method of assessing skeletal maturation. Done on a prepubertal girl to assess potential for growth.
Result
mild delay; typically 2 years less than chronologic age
echocardiogram
Test
Coarctation of the aorta may present in the neonatal period with cardiac failure or with hypertension. Bicuspid aortic valve occurs in approximately 30% of patients.
Routine transthoracic echocardiography may not obtain adequate visualization of aortic valve, thoracic aorta, and pulmonary veins except, perhaps, in newborns.
Result
bicuspid aortic valve; coarctation of the aorta; dilated aorta; partial anomalous pulmonary veins; left heart hypoplasia
cardiac MRI
Test
Cardiac MR (CMR) is more effective than echocardiography and allows excellent visualization of the entire thoracic aorta and great vessels, including pulmonary veins. [Figure caption and citation for the preceding image starts]: Cardiac MRI revealing normal aortic arch in "candy cane" configuration on the left, compared with a previously undiagnosed aortic coarctation, just after the origin of the left subclavian artery (arrow), detected by MRI in an adult woman with Turner syndrome with severe upper body hypertensionFrom the personal collection of Carolyn Bondy, MS, MD (NIH study) [Citation ends].
However, it requires sedation in the youngest patients and, thus, if clinical and echocardiographic evaluations appear normal, it is reasonable to wait until the girl is old enough to cooperate without sedation (usually 9 to 10 years).
Result
bicuspid aortic valve; coarctation of the aorta; dilated aorta; partial anomalous pulmonary veins; left heart hypoplasia
serum follicle-stimulating hormone and anti-Müllerian hormone
Test
An elevated follicle-stimulating hormone (FSH) and/or reduced anti-Müllerian hormone (AMH) predicts complete ovarian failure. However, ovarian potential cannot be predicted with certainty in young girls, as FSH levels elevate into the menopausal range at the age of normal puberty in those with ovarian failure.
Result
FSH-(abnormally) high; AMH-(abnormally) low
skeletal survey
Test
Performed in childhood at 5-6 years and 12-14 years to evaluate associated anomalies, such as wrist deformities and scoliosis.[3]
Madelung deformity (prominent distal ulna) is found in only approximately 5% of patients, but lesser degrees of wrist anomalies that can lead to functional problems are common.
Result
wrist deformities and scoliosis
pelvic ultrasound
Test
Performed in older girls and women.
The ovaries form normally in 45,X female fetuses, although most demonstrate accelerated oocyte death and ovarian degeneration into fibrous streaks.[19]
Result
immature uterus and streak ovaries
renal ultrasound
Test
Renal structural abnormalities affect approximately 25% of patients with Turner syndrome.[1][2]
Renal function is usually normal, but obstruction of the collecting system is associated with urinary infection and may need correction.
Result
horseshoe or single kidney, or duplicated collecting system
thyroid function tests
Test
Performed in all patients at diagnosis.
Autoimmune thyroid disease (Hashimoto thyroiditis and, less commonly, Graves disease) is a common complication in Turner syndrome. These should be repeated annually.
Result
hypothyroidism or hyperthyroidism
antithyroid antibodies
Test
Autoimmune thyroid disease (Hashimoto thyroiditis and, less commonly, Graves disease) is a common complication in Turner syndrome.
Result
positive
LFTs/gamma glutamyl transferase/alkaline phosphatase
Test
About 30% to 40% of patients develop a complication of "Turner hepatitis". These should be tested after the age of 10 years and repeated annually.
Result
elevated AST, ALT, gamma glutamyl transferase
fasting glucose and HbA1c
Test
Diabetes is a common complication in Turner syndrome. Annual screening for diabetes risk includes fasting glucose and HbA1c. These should be tested after the age of 10 years and repeated annually.
Result
elevated
serum lipids
Test
Dyslipidemia is common in Turner syndrome. These should be tested if ages 18 years or older, and if there is at least one risk factor for cardiovascular disease (check also regional recommendations).
Result
elevated
IgA level and tissue transglutaminase IgA
Test
Celiac disease is common in Turner syndrome. These should be tested from ages 2 years and repeated every 2 years until adulthood, and then if symptomatic, repeated every 5 years.[3]
Result
elevated
vitamin D levels
Test
Vitamin D levels should be checked every 2-3 years after the age of 9 years until adulthood and every 3-5 years thereafter.[3]
Result
may be low
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