What is skeletal dysplasia?
Skeletal dysplasia is an umbrella term for a group of disorders that affect bone and cartilage growth and hinder children’s growth and development. There are more than 450 types of skeletal dysplasia, which are categorised into 40 groups. Its major common characteristic is severe short stature also referred to as dwarfism.
Skeletal dysplasia is a genetic condition, each type of skeletal dysplasia is associated with a different group of genetic mutations which are present from birth. A genetic mutation is a change in your gene that can be caused by all kind of factors and often happens spontaneously. Whilst the individual types of skeletal dysplasia are rare, collectively skeletal dysplasia affects about 1 in 5,000 births.
Severity varies widely from person to person and is impacted by the type of skeletal dysplasia. Early diagnosis is key to ensuring the condition can be appropriately managed, often by a multidisciplinary team of specialists.
Hear advice from other parents whose children are also short in stature, compared with others their age. https://morethanheight.com/en/life-with-growth-disorders/advice-for-early-years-parents-of-a-baby-or-toddler-with-a-growth-disorder/
What causes skeletal dysplasia?
Skeletal dysplasia is caused by a genetic mutation, which can be passed down from a parent or could have arisen randomly in the child for the first time. A parent carrying a genetic mutation may not be affected or only affected mildly.
The genetic cause of 56 of the 450 types of skeletal dysplasia have been identified. Mutations in different genes can cause the same type of skeletal dysplasia. It is also possible for mutations in the same gene to cause different types of skeletal dysplasia.
Different types of genetic mutation affect the body in different ways. Generally, the genetic mutations associated with skeletal dysplasia disrupt the organisation of the growth plate, resulting in disruptions to skeletal growth and development. In some cases, other organs may be affected because the affected gene plays a functional role in tissues other than the skeleton such as the ears, eyes and brain.
What are the types of skeletal dysplasia?
Notable types of skeletal dysplasia include:
- Achondroplasia. During development, the cartilage does not convert into bone, resulting in dwarfism.
- Osteogenesis imperfecta. A genetic disorder characterised by fragile bones that break easily due to insufficient collagen production.
- Achondrogenesis. A group of severe disorders that affect cartilage and bone development. These conditions are characterized by a small body, short limbs, and other skeletal abnormalities.
- Hypochondroplasia. A form of skeletal disease characterized by very short stature.
- Thanatophoric dysplasia. One of the more severe types of skeletal dysplasia, causing a disproportionately small ribcage, short limbs and extra folds of skin on the arms and legs.
- Campomelic dysplasia. A condition characterised by distinctive facial features, bowing of the arms and legs and club feet.
What are the symptoms of skeletal dysplasia?
The symptoms of skeletal dysplasia vary depending on the type diagnosed. There are symptoms common to most types of skeletal dysplasia that are present from birth including:
- Large head size
- Narrow chest
- Short neck
- Small hands
- Widely spaced nipples
- Short stature
If your child is short in stature, keeping track of their growth can help identify if there is a problem early on. Compare your child’s measurements to the national average to see if they are within a healthy range.
Calculate your child’s growth
It is important to keep track of your child’s growth in order to identify if there is a problem early on. We recommend measuring your child every 6 months, which is now easier, with our simple to use growth calculator.
The exact symptoms vary with the type of skeletal dysplasia. The classic symptoms of the more common types of skeletal dysplasia are described below.
| Type of Skeletal dysplasia | Symptoms |
| Achondroplasia | • Short stature • Large head • Frontal bossing (large forehead) • Narrow chest • Short limbs • A trident shape of the fingers caused by more space between the middle finger and the ring finger |
| Hypochondroplasia | • Short stature • Large head • Stocky build • Short and broad hands and feet • Short arms and legs |
| Thanatophoric dysplasia | • Large head • Extremely short arms and legs • Extra folds (redundant) skin on the arms and legs • Short ribs and lungs |
| Pseudoachondroplasia | • Short fingers • Normal length at birth, short stature from about age 2 onwards • Restricted extension at the elbows and hips • Short arms and legs • Osteoarthritis (joint disease with joint pain and stiffness) • Waddling gait |
| Osteogenesis imperfecta | • Short stature • Easily broken bones • Blue sclera (the white of the eyes is coloured blue) |
| Achondrogenesis | • Large head • Small ribs • Short arms and legs • Small arms • Missing bones from the pelvis |
| Campomelic dysplasia | • Flat top of the nose • Frontal bossing (large forehead) • Bowing of the legs • Club feet • Small lungs and chest |
Are there any complications associated with skeletal dysplasia?
The severe growth problems associated with skeletal dysplasia can lead to further complications in the body including the brain, spinal cord, joints, heart, lungs, ear, nose, throat, and teeth. If the rib cage is not large enough to allow for proper lung development, skeletal dysplasia can be lethal.
How is skeletal dysplasia diagnosed?
If your child has skeletal dysplasia, they may be born with short stature or they may fail to grow as they age. If your child has other clinical signs or a family history of the condition, your doctor may suspect a diagnosis of skeletal dysplasia.
To diagnose skeletal dysplasia, your doctor will usually start with a physical exam to measure head circumference, birth weight, birth length, chest circumference and length of hands and fingers. Your doctor may then perform X-rays, magnetic resonance imaging (MRI) scans or computed topography (CT) scans to assess any issues in your child’s bones.
To confirm which type of skeletal dysplasia your child has, your doctor may recommend genetic testing. However, as the genetic mutation causing skeletal dysplasia has only be identified in 56 out of the 450 types, the exact genetic cause may not be established.
It is important you speak to your doctor if you have any concerns about your child’s height. Use this helpful guide on what questions to ask and what to expect from your visit. https://morethanheight.com/en/talk-to-your-doctor/visiting-your-paediatrician/
