Introduction

Acromicric dysplasia (AD) is a rare condition that affects how a person grows.¹ This reduction of growth causes people with acromicric dysplasia to be shorter than average, with changes to facial features and small feet and hands.¹

The condition affects people of all genders equally.¹ People with AD have a normal life expectancy and usually report a good quality of life and an ability to work.²

When people with AD are born, they are a normal height when compared to other people their age. However, this changes over time, as they do not grow as fast as other children.³ It is usually diagnosed at three years of age.³

What Causes Acromicric Dysplasia?

AD usually appears "sporadically," meaning that no one else in an affected person's family has the condition.¹ It was thought that people with AD were always one-off occurrences within families that were otherwise "normal".

However, more recent research has proved that AD is most likely passed down through families.² A gene known as FBN1 is the part of DNA that is passed down from parent to child. If the FBN1 gene inherited from either parent is mutated (changed from the “normal” FBN1 gene), this can lead to AD.³

Autosomal Dominant Inheritance

Autosomal dominant inheritance happens when one parent passes on a gene to the child.⁴ If one parent has the gene, there is a 50% chance that the child will inherit it.⁴ This is the kind of inheritance that causes AD.

Acromicric Dysplasia Symptoms

AD does not affect the person's mental capability, but it can cause differences in someone's body compared to "normal" development. These include:⁵

• Changes to the femur (thigh bone)
• Well-developed muscles
• Changes to the bones of the hands
• A hoarse voice
• Carpal tunnel in older people with AD
• Joints which are unable to move as they should
• Spines which are different from normal
• Misalignment of the hips
• Slower than usual maturing of the bones
• Getting ear and/or chest infections over and over
• Face features different from the norm

Acromiric Dysplasia Facial Features 

Certain facial features are common in people who have AD. These are discussed below.

Rounded Face

People with AD have a more rounded face than is generally seen in people.³

Small Mouth

AD causes people to have a small mouth.³ They often have lips that are thicker than average, which also distinguishes their mouths from people who do not have AD.³

Pronounced Philtrum

The groove between the top of your upper lip and the bottom of your nose is called the philtrum. In people with AD, this is longer than in people who do not have AD.³

Eyelash length

The eyelashes of people with AD tend to be longer than those without AD.³

Noses and nostrils

The nostrils of people with AD tend to be higher than in people without AD, causing an "upturned" look.³ The nose also tends to be rounder, or "bulbous," in people with AD.³

Craniofacial abnormalities

The skull can develop differently in people with AD. These are listed below.

Microstomia

If someone has a small opening to the mouth, which affects things like eating.⁶ People in AD can have this, which can make things like visiting the dentist difficult.⁵

Tooth Crowding

If there is not enough room for the teeth inside the mouth, the teeth can begin to overlap. This is known as tooth crowding. This is more common in people with AD than in people without AD.⁵

Diagnosing AD

There are several methods that your doctor will assess you to diagnose AD.

Symptoms

Your doctor will ask you questions about your health and your body, both in the past and now.⁷ This will help them to understand whether you have the telltale signs of AD.

Examination

Your healthcare practitioner will ask to physically examine you, especially your hands, feet, hips, joint movements, and face.⁷ By doing this, they will see if your body fits the categories of a person who has been affected by AD.

Imaging

Your doctor may refer you to have x-rays. on your hands or legs, as people with AD have differences to the bones of the hand and thighs that are visible on an x-ray.⁷

X-rays are a fast, painless procedure that is normally done in the hospital.⁸ You will usually be asked to lie on a table or place your body in a specific position so that the radiographer (person operating the x-ray machine) can take an image of the correct part of your body.⁸ 

When the image is taken, the x-rays will pass through your body, but you will not feel or see them.⁸ Your doctor will then look at your x-rays to see if your bones have the changes caused by AD. 

Genetic Testing

If more certainty is needed, your doctor may take a sample of blood or saliva to have it tested in a laboratory.⁹ This will help them see if you have inherited the mutated FBN1 gene that causes AD.

Differential Diagnoses

Some conditions have similar symptoms to AD, so your healthcare team will usually try to rule these out when diagnosing you. These conditions include:

Myhre Syndrome

Shortness and changes to facial features are common in Myhre syndrome. However, it is different from AD as the people with Myhre syndrome tend to have intellectual difficulties and heart problems.

Geleophysic Dysplasia

Geleophysic dysplasis also causes joint limitations, shortness, and small hands and feet. However, it also causes the heart valves to thicken, which is not the case in AD.

Weill-Marchesani syndrome

This syndrome causes shortness and joint stiffness. However, it also causes changes to the lens inside the eye, which is not true of AD, and this can help your doctors to tell them apart.

Acromicric Dysplasia Treatment

There are several treatments that can help people with AD, though it cannot currently be cured. These treatments are discussed below.

Physiotherapy

People with AD may have physical therapy recommended to them. This helps the person’s joints stay mobile, reducing the changes that the range of movement in joints will be limited later in life.

Regular lung checks

Some people with AD have chest infections quite often. If this is the case, your doctor will work with lung specialists to monitor you and treat the problems as necessary.

Orthopaedic treatment

You may be seen in the hospital by specialists in bones and joints, otherwise known as the orthopaedics team. People with AD are usually referred to this portion of the hospital for hip problems.

This problem is called hip dysplasia, and it occurs in children when the joint of the hip does not form correctly.

Adults with AD may need to see the orthopaedic team due to carpal tunnel, which is common in people with AD. Carpal tunnel syndrome is caused by pressure on a nerve in your hand, which can cause:

• Problems when you try to grip something
• Aching fingers, arm or hand
• Tingling in your hand
• Numbness in the hand

Treatment for carpal tunnel syndrome often involves using a splint on your wrist to relieve the pressure that is being put on the nerve.

Dental treatment

If there is a problem such as tooth crowding, then you may be referred to a dentist or orthodontist who will assess the mouth and determine if any treatment is necessary.⁵

Growth Hormone Therapy

Some early tests have been done to see if AD will respond well to growth hormone therapy. However, more research is needed on this treatment.

Summary

AD is a very rare disease that is passed down through families. It affects people in many ways physically but does not cause learning difficulties.

There are treatments available to help people with AD manage their symptoms, and further research is being done into growth hormone therapy. However, more information is needed on this topic.

If you think that you or someone you know may have AD, it would be best to make an appointment with the GP to discuss with a medical professional who could help with the diagnosis.