Restricted growth (dwarfism)

Being short is not, in itself, an illness. It is a feature of the body that people live with, work with, drive with, raise children with and grow old with like any other. What needs medical attention is not the height but what lies behind it: the causes of restricted growth are many and very different from one another. Everything else follows from the cause — whether treatment is called for, what needs watching, what to expect later on. So the useful question here is not how to get taller, but what exactly this condition is and what to keep an eye on.

A word about words. Medicine draws the line at an adult height of roughly 147 centimetres when it speaks of restricted growth. The word "dwarfism" appears in reference books and in search boxes, which is why it stands in the title, but it is better not to use it when speaking to a person: many find it hurtful. The neutral terms are short stature, or a person of short stature.

Proportionate and disproportionate growth

The first thing a doctor looks at is the build.

Proportionate short stature: arms, legs, trunk and head relate to each other in the usual way, the person is simply smaller. This is how familial short stature looks, and so do growth hormone deficiency, the aftermath of a serious long-term illness, and undernutrition in childhood.

Disproportionate short stature: the parts of the body grow differently — the trunk may be of usual length while the arms and legs are shorter, mainly in the segments nearest the shoulder and hip, and the head is relatively large. This is the picture of the skeletal dysplasias, the conditions affecting how bone and cartilage develop.

The distinction is not cosmetic. It rules out half the possible causes straight away and decides which investigations are worth doing and which are pointless.

Why growth may be limited

There are dozens of causes, but they fall neatly into a few groups.

• Skeletal dysplasias. The best known is achondroplasia: a change in a single gene disrupts the turning of cartilage into bone, and the long bones grow less. In roughly four cases in five the change is a new one, arising by chance, in parents of ordinary height. Several hundred skeletal dysplasias are known, and achondroplasia is the commonest.
• Growth hormone deficiency. The pituitary gland does not make enough, whether because of how it developed or because of a tumour, an injury or a treatment. This is where height responds best to treatment.
• Genetic syndromes in which short stature is one feature among several: Turner syndrome in girls, Noonan syndrome, Prader-Willi syndrome and others.
• Long-term childhood illness — serious kidney, heart or bowel disease, gluten intolerance, untreated underactive thyroid. The body spends its resources on the illness and growth slows. It often picks up again once the underlying condition is controlled.
• Inadequate or unbalanced nutrition, and also low weight and length at birth where the child never catches up.
• Familial short stature and constitutional delay. In the first, the parents are short and the child is simply following the family line. In the second, the child lags behind classmates but also matures later and catches up afterwards. Neither is an illness.

When to take a child to the doctor

What matters is usually not the height itself but the trend. Reasons to raise it with a doctor:

• the child is growing noticeably more slowly than others of the same age, or has gained less than usual over the past year;
• the child is drifting downwards across the growth chart, falling further behind — a single point on the graph says far less than the direction of the line;
• the height does not fit the family picture: both parents are tall and the child is among the shortest in the class;
• there is visible disproportion, with arms and legs short relative to the trunk;
• growth has slowed alongside other changes: weight gain, listlessness, feeling the cold, delayed puberty;
• the child was born small and by two or three years old has not caught up.

The place to start is measuring, not waiting. Measure the child regularly and always the same way, note the date and the figure, and bring that list to the appointment: your own growth curve is worth more than any amount of guesswork.

How it is investigated

Tests are chosen according to the suspected cause, not ordered just in case.

It begins with the history and the measurements: height, weight, body proportions, the parents' heights, how the pregnancy and birth went, when the teeth came through and when puberty started, what illnesses there have been. Blood tests usually follow, ruling out thyroid disease, coeliac disease, kidney disease and nutritional deficiencies; in girls a chromosome study is added, because Turner syndrome is easy to miss.

An X-ray of the hand shows the bone age, which tells how much growth is still in reserve. Where growth hormone deficiency is suspected, specific stimulation tests are done and sometimes a scan of the brain. Where the build is disproportionate, a skeletal survey and genetic testing are arranged; the genetic result gives the condition its exact name and, with it, the list of what to monitor.

Sometimes the features are visible before birth on ultrasound, from shortening of the long bones in the third trimester. Where a family already includes someone with a known genetic condition, it is worth seeing a genetics service: they explain the probabilities and what testing is available.

Achondroplasia: what is monitored

What follows changes life more than centimetres do, so anyone the subject touches should read this section in full.

In babies, narrowing of the foramen magnum. This is the opening at the base of the skull through which the spinal cord passes; in achondroplasia it can be narrow, and the junction between head and neck may be compressed. That is why babies in the first year are followed particularly closely and, where needed, have a scan and a sleep study. The warning signs are pauses in breathing during sleep, unusual floppiness or listlessness, weakness in the arms or legs, poor head control, difficulty feeding, and heavy sweating while asleep. With any of these, seek medical help without delay: surgery done in time relieves the compression.

Pauses in breathing during sleep also occur later, in adults included, because of the shape of the middle of the face and the upper airway. The signs are loud snoring with pauses, waking unrefreshed, morning headache and daytime sleepiness. It is treatable, and worth treating.

Ear infections and hearing. The tube connecting the middle ear to the throat is shorter and narrower than usual, so middle ear infections and fluid behind the eardrum are common. The key thing is not to miss hearing loss in the years when a child is learning to speak; hearing is checked regularly.

Spinal canal narrowing in adults. With the years, the canal carrying the spinal cord can narrow. It shows up as pain in the lower back and legs, numbness and weakness that build up with walking and standing and ease on sitting down or leaning forward. That warrants a planned appointment. By contrast, sudden weakness in the legs, numbness around the genitals and back passage, or loss of control of the bladder or bowels is an emergency: call an ambulance at once (in Spain, Italy, Portugal, Poland and Ukraine, on 112).

Bowing of the legs, the shape of the spine, weight — extra kilos load the joints and back — and crowding of the teeth in the jaw are all watched as well.

What treatment can and cannot do

Two quite different situations need separating here.

Where growth is limited by a lack of growth hormone, the hormone is given by injection and it works: many children reach an adult height at or near the average. Growth hormone is used in some other situations too, for example in Turner syndrome, or in children born small who have not caught up. Treatment is long, usually until growth finishes, and needs regular follow-up.

In the skeletal dysplasias growth hormone makes little appreciable difference: the problem there lies not in the hormone but in the cartilage itself. For achondroplasia, medicines aimed at the disturbed mechanism of bone growth have appeared in recent years; they are prescribed to children through specialist centres and are discussed with the specialist looking after the child.

Limb-lengthening surgery exists, but it is not a cosmetic procedure: several stages, months in frames, pain, and a risk of complications. The decision is made carefully, and not on the child's behalf. Far more often, surgery in skeletal dysplasias is done for other reasons — to relieve pressure on nerves, straighten the legs or correct a deformity of the spine. And on the whole, most of the medical care here is aimed not at height but at joints, back, hearing and breathing in sleep: those are what determine how a person feels.

Everyday life

Most people with restricted growth live as long as anyone else; a few specific conditions carry particularities that the treating doctor will set out plainly.

The practical side is solved with adaptations, and solved well: steps and reachers at home, light switches and shelves moved to a comfortable height, pedals and seat adjusted to the driver, a chair and desk of the right height at school and at work, clothes and shoes altered or made to measure. A handful of simple changes is usually enough, after which nobody thinks about it daily. On the medical side, joints and back are worth keeping in mind: swimming and cycling suit well, whereas sports involving impact on the spine and somersaults are generally not advised in skeletal dysplasias — something to work through with the doctor case by case rather than banning everything outright.

Other people's reactions deserve their own paragraph. The stares, the comments, the strangers' hands reaching to pat a head — almost everyone meets these, and by many families' account they weigh more heavily than any orthopaedic problem. A child is helped by having a simple answer rehearsed in advance; a school, by talking to the class before the questions start; an adult, by contact with others who have been through the same. Organisations of people of short stature exist in most countries, and the nearest one can be found through the treating doctor or the genetics service. Entitlement to support and benefits is set by the law of your own country: ask at your local social services.

Online consultation

Care at a distance suits this subject unusually well: it involves far more conversation and reading of reports than physical examination.

An online appointment works for plotting a growth curve from your own measurements and judging whether there is a reason to investigate; for sorting out which tests and images are needed and which are superfluous; for explaining a genetic report in plain language; for building a monitoring plan once the diagnosis is known — what to check and how often; for going over the signs that call for care in person; and for preparing the visit to the endocrinologist, the orthopaedic surgeon or the geneticist.

Have ready: all height and weight measurements with their dates, your own height and the other parent's, letters, images and genetic reports if any exist, and the list of medicines. If this concerns a baby with achondroplasia, note how the baby sleeps and breathes at night, how the head is held and how feeding goes — those observations matter most to the doctor.

This material is for information only and does not replace medical advice.