Teaching Case

A 16-year-old female patient presented with complaint of primary amenorrhoea.
Clinically she was short with prominent epicanthal folds, multiple facial naevi (Fig. 1) and small fourth finger of both hands. Perinatal history was unremarkable.
Previous images of USG pelvis revealed a streaky uterus with non-visualised ovaries. A skeletal survey was requested.

The skeletal survey revealed short fourth metacarpal in both hands - Positive metacarpal sign (Figure 2).
AP view of both feet delineated short fourth and fifth metatarsals (Fig. 3).
Bilateral AP view of knee joints showed bowing with widening of the medial femoral epicondyles and linear striated trabaculae (Fig. 4).
There was no evidence of scoliosis, maldeveloped ribs and clavicles or narrowed pubic arch. On plain CT skull base, the radiographic findings were confirmed. Odontoid process and atlas appeared normal.

Turner syndrome is an X chromosomal disorder with variable karyotypic abnormalities and protean clinical manifestations in females. It was first described as a distinct entity in 1938, by Henry Turner, in seven female patients with sexual infantilism, webbed neck and cubitus valgus [1].
It is characterized by the presence of a single normal functioning X chromosome. Cases are mostly sporadic and occur due to non-disjunction of reproductive cells. Unlike other trisomies, there is no correlation with maternal age.

Types[1]:
1. Complete monosomy (45XO): Commonest
Even though it is relatively common, almost all 45 XO fetuses will spontaneously abort.
2. Partial monosomy: Structurally altered X chromosome
3. Mosaicism: XO + another sex karyotype

Our patient was referred for chromosomal analysis that revealed 45XO karyotype, thus confirming the diagnosis (Fig. 5).

Clinically Turner syndrome accounts for 1/3rd cases of primary amenorrhoea. Patients may present with short stature, lymphoedema of the hands and feet, shield chest with widely spaced nipples, low hairline, low-set ears, infertility, obesity, small finger nails, prominent epicanthal folds, micrognathia, high arched palate, pigmented moles, visual impairments (glaucoma), hearing loss, high waist-to-hip ratio and nonverbal learning disability. Turner syndrome manifests itself differently in each woman, therefore, no two individuals will share the same features [1].

Associations: Hypertension, glucose intolerance, inflammatory bowel disease, Hashimoto thyroiditis and ovarian dysgenesis.

Antenatal serological markers: Serum AFP is decreased, beta HCG and serum inhibin
may be elevated in hydrops fetalis.

Imaging perspective [2]:
Antenatal ultrasound may reveal cystic hygroma - typically septated, increased nuchal thickness, increased nuchal translucency, coarctation of the aorta, bicuspid aortic valve, horseshoe kidney / pelvic kidney, IUGR, short fetal limbs and hydrops fetalis (due to lymphatic failure).

Findings in adulthood include scoliosis, short 4th metacarpal (positive metacarpal sign), narrowed scapho-lunate angle (positive carpal sign), abnormal medial femoral condyle, Madelung deformity, short stature, webbed neck, cubitus valgus, hypoplasia of atlas or odontoid, thin clavicles and ribs, osteoporosis of spine and delayed epiphyseal fusion.

On sonography, uterus and ovaries may appear streaky. Renal anomalies may also be delineated.

Prognosis is variable and depends on associated anomalies. While the vast majority of fetuses abort in the second trimester, some may have long life expectancy. Cases with mosiacism do much better. Mental development is unaffected.

Treatment [1, 2]: Directed to minimize symptoms.
Growth hormone to attain adult height.
Oestrogen replacement therapy to promote development of secondary sexual characteristics. It is crucial for maintaining good bone and cardiovascular integrity.
Uterine maturity is associated with oestrogen use and history of spontaneous menarche. Oocyte donation for pregnancy may be fruitful.