Diastrohic literally means “twisting” and dysplasia goes to mean “atypical growth”. The condition, diastrophic Dysplasia (DD) is a very rare type of dwarfism. It is a rare condition leading to extremely restricted growth with disproportionate stature. Disproportionate means that the arms and legs are short in comparison to body length.
How is diastrophic dysplasia caused ?
Diastrophic dysplasia is transferred by heredity. It has an autosomal recessive pattern of inheritance meaning that both parents need to carry the defective gene for a child to have the condition, diastrophic dysplasia. For couples who have one child with this dysplasia, there is a 25% chance with each following pregnancy that the child will have diastrophic dysplasia.
What is the pathology behind diastrophic dysplasia ?
Though the basic pathology is a small physique, in fact, the more severe problems in this condition are related to joints. It arises because of a single gene change, in the genes coding for cartilage that result in defective extracellular matrix. The gene thought to be responsible for diastrophic dysplasia lies within chromosome 5, and it is the code for a key sulphate transporter, responsible for transporting sulphur into cartilage. The gene responsible for this condition is known as the “diastrophic dysplasia sulphur transporter” gene.
The result is joint abnormalities such as load deformation especially if made to bear weight, abnormal or limited mobility, and the hallmark, early and marked degenerative changes of the joint.
How does diastrophic dysplasia affect your life ?
When the early jolt of the diagnosis has worn off, many parents are concerned and apprehensive to know what their child’s future will be. As with many causes of short stature, diastrophic dysplasia is primarily a physical condition- people with this condition have an absolutely standard range of intelligence, occupy positions in many areas of society and have diverse abilities.
Most people live normal, happy lives (with a normal life-span) although there will, of course, be some physical limitations, seen with the symptoms of diastrophic dysplasia. For instance, if there is cleft palate, there will be speech defects.
How is diastrophic dysplasia diagnosed ?
Diagnosis can be provided by ultrasonography, which is feasible only after the first trimester. Prenatal diagnosis also can be accomplished by chorionic villus sampling and DNA linkage studies. Also, families affected by diastrophic dysplasia require careful genetic counselling.
What is the clinical presentation of diastrophic dysplasia ?
The clinical findings of short-limbed short stature, joint contractures, end to end fusion of the phalanges of the fingers (symphalangia), hitchhiker’s thumbs (thumbs having an angle close to 90º), deformities of the feet, increased incidence of cleft palate and warping of the ear lobes (cauliflower/misshapen ears) are recognisable in the newborn infant.
By short stature, we mean pathologically short, that is newborn diastrophic babies measure around 42 centimeters (16.5 inches) in length. In adults, the height can vary widely, measuring 87-140 cm (ie. 34-55 inches).
Lumbar Lordosis (increased curvature of the lower spine) and rigid kyphoscoliosis (progressive upper spinal curvature) develops very prematurely and early in these patients.
The most significant and disabling health problems in affected adults are degeneration of the hip and other joints, before time, leading to early degenerative osteoarthritis.
What are the treatments/ interventions required for children with diastrophic dysplasia ?
- For deformities of the fingers & hands: Despite great disability and limitations, children become skilled at using their hands. Surgical invention is best avoided unless it is done for the sole purpose of improving function. Most children with this dysplasia can use their hands for even the most complicated tasks. Occupational therapy for developing fine motor and adaptive needs, to overcome hand abnormalities is required. A variety of adaptive devices and alternative adaptive strategies may be used in order to overcome the disabilities.
- Misshapen ears: Gauze pads can be taped over the ears when the swelling first appears and a gauze headband can be placed for compression until the swelling subsides, a period extending to 3-4 weeks. So, by this procedure the ears are reshaped. The swelling of the ears is purely cosmetic and does not impair hearing.
- Surgical Correction for club shaped feet/ hip joint problems: This could entail elaborate correction procedures and long durations spent in casts.
- Spinal Defects: Because of lumbar lordosis and kyphoscoliosis, it is very important to have your child followed by an orthopaedic specialist, especially one well versed with diastrophic dysplasia, who can examine your child’s spine. The diastrophic child afflicted with cervical kyphosis of the neck will also need surgical correction and the use of a neck traction device for variable durations. For the duration of these long-drawn recoveries, children should use his/her hands still as much as possible, with various games, projects and toys. Physical rehabilitation like swimming and stretching exercises is suggested to strengthen the muscles, the joints and the bones.
What is the care to be taken by children with diastrophic dysplasia ?
The administration of anaesthesia is to be done with special care. Firstly, the cervical spine could have abnormalities, like kyphosis or abnormal curve.
The endotracheal tube which is placed in the trachea, to assist in breathing during general anesthesia usually requires the neck be stretched it to be inserted. This can be potentially dangerous if the cervical spine has defects such as kyphosis.
Limit the number of surgeries on bone and cartilage to those clearly essential for function. The best possible treatment consists of a sensible diet, regular gentle exercise and physiotherapy, and routine check-ups by the paediatrician, throughout childhood to identify and treat complications as soon as they arise. Surgery to increase the height and length of limbs is not recommended, because of complications of joint contractures, osteoarthritis and severe joint degeneration.
Disclaimer: The content provided here is meant for general informational purposes only and hence SHOULD NOT be relied upon as a substitute for sound professional medical advice, care or evaluation by a qualified doctor/physician or other relevantly qualified healthcare provider.
