Achondroplasia

Also called Dwarfism, Restricted growth

The commonest cause of restricted growth. A physical difference, not an illness, with a few specific medical risks.

What it is

Achondroplasia affects around 1 in 25,000 births and is the commonest cause of disproportionate short stature. It is caused by a change in the FGFR3 gene affecting cartilage becoming bone.

Around 80% of cases are new mutations in families with no history.

Intelligence is entirely unaffected. Life expectancy is close to average with good medical care. It is a physical difference to be accommodated, not a condition to be cured, and the language people use about it matters: dwarf and person of short stature are both used within the community, midget is not.

There are specific medical risks that need monitoring, and the most serious is compression of the spinal cord at the base of the skull in infancy, which is why babies are monitored closely.

Signs you might notice

Disproportionate short stature: an average-sized trunk with shorter arms and legs.

A larger head with a prominent forehead.

Restricted elbow extension, and a curve in the lower back.

In infancy: watch for breathing pauses, excessive sweating during sleep, and delayed motor milestones, which may indicate craniocervical compression.

Later: recurrent ear infections and hearing loss, sleep apnoea, and spinal stenosis in adulthood causing back and leg pain.

How it can affect day-to-day life

The world is built for a different height, and that is the daily reality: light switches, counters, cash machines, public transport, car pedals. Adaptations are practical rather than medical.

Spinal stenosis in adulthood is the commonest significant problem and causes pain, numbness and difficulty walking. It is treatable, and it is often attributed to ordinary back pain.

Attitudes are the harder part. People with restricted growth report being photographed without consent, touched, and treated as a spectacle. That is not a minor irritation.

Growth hormone does not work for achondroplasia. A newer drug, vosoritide, is available in some circumstances and its long-term role is still being established.

Supporting someone well

Keep the specialist follow-up going: neurology in infancy, hearing, sleep studies, and spinal review in adulthood.

Treat ear infections promptly and check hearing regularly, since glue ear is common and affects speech.

Adapt the environment rather than expecting the person to manage: step stools, reachers, adapted pedals, lowered work surfaces.

Take new back or leg pain, numbness or difficulty walking seriously in an adult; it may be spinal stenosis.

Do not comment on height, do not photograph, do not pick children up without asking.

Use Access to Work for workplace adaptations.

Where to get help

The Restricted Growth Association UK provide peer support and practical advice.

Ask for referral to a specialist skeletal dysplasia service.

Breathing pauses in an infant, or new neurological symptoms at any age, need prompt assessment.