Introduction:
The name skeletal dysplasia is derived from the Latin word “dysplasia,” which means “bad growth.” Skeletal dysplasia is an inherited genetic condition that includes more than 450 disorders of bone. In this condition, abnormal development of the bones, connective tissues, and cartilage creates obstacles to the children's average growth and development. As a result, these children will generally have short stature.
What Is Skeletal Dysplasia?
By definition, skeletal dysplasia or osteochondrodysplasia are inheritable bone diseases affecting the development of the skeletal system that can affect either a single bone or several other bones and connective tissues. They were referred to as “dwarfism” or “little people” in the earlier days as these adults were generally less than 4 feet and 10 inches.
What Are the Types of Skeletal Dysplasia?
Skeletal dysplasia is a group of bone disorders where there are more than 400 types recognized until now. However, the most common ones encountered in clinical practice are:
1. Achondroplasia-
-
It is the most common type.
-
It is characterized by spinal stenosis, a compressed lower spine, short limbs and thick fingers, and a prominent forehead.
2. Osteogenesis Imperfecta-
-
It is also known as “brittle bone disease.”
-
Patients have fragile bones and hence are highly susceptible to fractures.
-
Soft and thin skull.
-
Short stature with deformed bones that are irregular and thickened.
3. Thanatophoric Dysplasia-
-
These children will have short stature, bowed legs, prominent forehead with a depressed nasal bridge.
-
Small rib cage, flattened vertebrae, and cloverleaf skull.
-
Bowing of thigh bones (femur), clubbed feet.
-
The ribs appear to be missing.
-
Ambiguous genitalia (the genitalia are not clearly defined, whether male or female genitalia).
-
Flattened face and prominent forehead.
-
Campomelic dysplasia is highly fatal in newborns compared to other skeletal dysplasias.
5. Achondroplasia-
-
Small thorax or chest is seen.
-
Spine bone is not fully mineralized or underdeveloped.
-
Short limbs.
-
They are characterized by short arms and legs with broad feet and hands.
What Is the Cause of Skeletal Dysplasia?
The etiology of skeletal dysplasia is multifactorial. The common causes that are known to cause this condition includes:
-
More than 50 % of skeletal dysplasia is due to genetic conditions.
-
It is an inherited genetic condition that gets passed from parents to children.
-
Any spontaneous mutations during pregnancy.
-
Exposure to toxic substances or agents (teratogens) that causes disturbances during growth and development in utero.
-
In rare circumstances, they are also seen in children without any family history.
What Is the Incidence of This Condition?
-
It is a rare genetic and congenital disorder. It affects only one in 5000 live births.
-
It has no gender predilection.
-
Though it has no racial predilection, it is more common in Ashkenazi Jews.
What Are the Clinical Features of Skeletal Dysplasia?
Most children are symptomatic and diagnosed right from birth. Other children may develop the symptoms as they grow older. Skeletal dysplasia affects any part of the body.
The most common symptoms seen are:
-
Instability of the cervical spine (they cannot support the head).
-
Spinal stenosis (the spinal canal narrows creating tension and compressing the spinal cord).
-
Kyphosis (it is a spine disorder causing excessive curvature of the spine around the upper back).
-
Scoliosis (abnormal spine posture due to curvature in the wrong direction).
-
Bowing of legs or knocking knees.
-
Clubbed feet.
-
Stiffness of the joints and premature arthritis.
Other symptoms are:
-
Short stature with a long trunk, short extremities- hands and legs.
-
Prominent forehead and relatively large-sized head.
-
Brittle bones and malocclusion (crowding of teeth).
-
Hearing and visual disturbances. Recurrent ear infections that might cause hearing loss.
-
Cervical medullary compression (a condition that compresses the spinal cord resulting in numbness and difficulty in walking).
-
Hydrocephalus (the cerebrospinal fluid gets accumulated in the ventricles of the brain).
-
Mental retardation and developmental delays.
How to Diagnose Skeletal Dysplasia?
Most cases of skeletal dysplasias are diagnosed during prenatal screening and ultrasounds. The fetal skeleton is routinely monitored during ultrasounds from the 20th week onwards. Some skeletal dysplasia is only evident during the third trimester. If there is any known family history, then genetic testing is indicated to rule out the condition in the fetus. If skeletal dysplasia is not diagnosed before birth, then it may be diagnosed soon after birth. The pediatrician looks for any signs and symptoms during a routine examination. One typical sign is that the head tends to grow larger than the rest of the body.
Other tests that are essential for the diagnosis are:
-
X-rays- X-ray imaging is used to detect the abnormalities of the bone structure.
-
Low-Dose Fetal Computed Tomography- It gives a three-dimensional and detailed imaging of the bone and surrounding structures.
-
Magnetic Resonance Imaging (MRI)- It is more advanced that gives detailed, more precise information than the computed tomography scan. However, it is advised only in children older than six months.
-
Ultrasound of the Brain- Sometimes, ultrasounds of the brain are also advised to detect abnormalities.
How Is Skeletal Dysplasia Treated?
There is no complete cure for skeletal dysplasia. However, the treatments can provide symptomatic relief to the patient. Each skeletal dysplasia is different; the treatment depends on its severity. In mild cases, adequate time is given before starting the treatment. The treatment aims at making the baby comfortable and relieving pain.
-
Physical Therapy- To strengthen the muscles and provide joint movements.
-
Back Braces- They are advised to treat the spine problem, curving and bowing.
-
Diet- Diet counseling is given to help in providing proper nutrition and avoiding obesity.
-
Growth Hormone Treatment- In the case of dwarfism, they are given to promote growth.
-
Orthodontic Treatment- They are used for treating malocclusion and skeletal defects.
Surgical Management-
Surgeries are advised to correct the deformities of the bone.
-
Spinal Stenosis- The excess bone will be removed around the spinal cord by a neurosurgeon, and the orthopedic surgeon stabilizes the spinal cord with the help of screws and rods.
-
Scoliosis and Kyphosis- Spinal fusion surgery is indicated to correct this condition. Screws and rods are attached to the curved position of the spine and thus straighten the curvature. Bone chips are employed at the affected part to promote bone growth.
-
Limb Lengthening Procedure- Short extremities may interfere with daily activities. Hence the bones are cut, and a device is adjusted within the bone and pulled apart gradually, thus promoting bone growth. They are repeated several times in a month until the desired length is achieved.
-
Osteotomy- They have indicated if the shape is not proper and crooked, the ends of the bones are cut and straightened, then secured with screws and metal plates to hold in the new alignment.
-
Brain Surgery- They are indicated in cases of hydrocephalus, where the excess cerebrospinal fluid is drained to relieve pressure.
-
Surgery for Cleft Palate- The cleft palate is a condition where there is an opening or slit in the roof of the palate.
-
Ear Infections- The drain tubes are inserted in the middle ear to prevent chronic infections and hearing loss.
Postoperative follow-ups are essential to assess prognosis and development. The children are monitored continuously until they enter adulthood for their well-being.
Conclusion-
Skeletal dysplasia is a rare disorder that causes several health complications. They are often diagnosed even before birth, and appropriate treatments can improve the child’s condition. The important part is that regular follow-ups are mandatory that assess the quality of life. If you have a known family history of skeletal dysplasia, then genetic testing should be done. Parents should be well informed and should take care of their child’s mental health. This is because many children may have low esteem and confidence due to their short physical appearance. This can be overcome only by the motivation provided by their parents and other family members.
