During an emergency surgery, I saw a five-year-old girl with her mother, who presented with a sore throat. At the end of the consultation, her mother commented that she was concerned her daughter was small for her age and wondered if she needed to worry about it.
I plotted the child's weight and height on a growth chart and noted both were around the 25th centile. Both her parents were short and there were no other developmental concerns, so I reassured her mother but advised her to return any time in future if she was still concerned.
The girl returned to the surgery two years later with her mother, who said she was still concerned because her daughter was the shortest girl in the class and some of her friends had commented about her height.
General examination was unremarkable except that I noticed the child's hands and feet seemed slightly puffy. I referred her to a paediatrician and was surprised to learn later that she has Turner syndrome.
Chromosomal abnormality
Turner syndrome, one of the most common chromosomal abnormalities, occurs when there is a complete or partial absence of one sex chromosome in a female. Most patients are 45X karyotype, but about 15% are mosaics (45X/46XX or 45X/47XXX); 99% of fetuses with 45X karyotype spontaneously abort.
Turner syndrome is also sometimes called gonadal dysgenesis. It occurs in around one in 2,500 live female births. There is no associated familial inheritance pattern and there are no clearly established risk factors. Maternal age is not a risk factor.
Around a third of patients are diagnosed as babies, around a third in childhood and the remainder in adolescence or adulthood. Children often present with slow growth. Older children may present with absent or delayed puberty, although about 30% of cases have some spontaneous pubertal development.
Primary amenorrhoea is often a feature. Adults may present with infertility or a history of recurrent miscarriage.
The most common physical signs of Turner syndrome are short stature, oedema of the hands and feet, and redundant nuchal skin. Patients with the syndrome may also have low-set ears and a low hairline.
Some patients have wide epicanthal folds, ptosis and/or upward-slanting palpebral fissures. Ptosis, nystagmus, cataracts, amblyopia and myopia may develop.
Patients typically have a short webbed neck, a shield-like chest with widely spaced nipples and cubitus valgus (a wide carrying angle of the arms). A high palate, hyperconvex nails, excessive naevi and telangiectasia may also be features.
Cardiovascular complications can occur in around 20% of patients with Turner syndrome (see box). Renal malformations can also occur, including horseshoe kidney, duplication of the collecting system, hydronephrosis and malrotation.
Deafness may develop secondary to chronic otitis media. However, 50-70% of affected individuals have a sensorineural hearing impairment.
The ovaries are replaced by fibrous streaks (streak gonads). However, spontaneous puberty can occur in around 5-15% of patients. There is an increased risk of developing autoimmune conditions.1
Scoliosis occurs in around 10% of adolescent girls with Turner syndrome and may contribute to short stature. Scoliosis screening is therefore usually undertaken. There is also increased risk of congenital hip dislocation.
Investigations and treatment
Karyotyping is needed for the diagnosis to be made. Once the diagnosis is made, other investigations are usually performed, including an echocardiogram to exclude cardiac abnormalities, and renal ultrasound.
Human growth hormone is given to some patients and it adds a median 5.1cm to their final stature. It is usually started from the time the patient drops off the normal growth curve until around the age of 12-14 years.2
The major impediment to successful growth hormone treatment is late diagnosis. For girls diagnosed very late with only a small time window for treatment, some paediatricians add oxandrolone, a non- aromatisable oral androgen, to growth hormone treatment to promote linear growth.3
Gonadal failure is treated with estrogens and progesterone. Starting estrogen too early or using doses that are too high can compromise adult height. Estrogen is usually started at 12-15 years. Treatment usually begins with continuous low-dose estrogens and as patients become older, they are usually given the combined oral contraceptive pill.
It is recommended for all patients to have BP, TFTs, blood glucose and cholesterol checked annually. They should be tested for coeliac disease and have a baseline hearing test. Screening for amblyopia and associated eye disorders is recommended.
Prognosis
The outlook for people with Turner syndrome is usually very good. Although most patients are healthy, it is important that they are regularly followed up to screen for any associated conditions that may occur.
Patients are usually shorter than average and although most are infertile, assisted fertility is often successful. However, life expectancy may be reduced due to complications of heart disease and diabetes.
- Dr Newson is a GP in the West Midlands
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References
1. Jorgensen KT, Rostgaard K, Bache I et al. Autoimmune diseases in women with Turner's syndrome. Arthritis Rheum 2010; 62(3): 658-66.
2. Kirk J. Indications for growth hormone therapy in children. Arch Dis Child 2012; 97(1): 63-8.
3. Zeger MP, Shah K, Kowal K et al. Prospective study confirms oxandrolone-associated improvement in height in growth hormone-treated adolescent girls with Turner syndrome. Horm Res Paediatr 2011; 75(1): 38-46.
