What Is Cockayne Syndrome?
Cockayne syndrome is a rare genetic disorder characterized by growth failure, abnormal sensitivity to light, microcephaly (small head), and premature aging features. It often starts in infancy, and as the individual grows, symptoms may worsen. It is a multisystem disorder, and it can also affect the nervous system, cause vision problems, tooth decay, bone abnormalities, hearing loss, and difficulty in learning. The affected individuals find it very difficult to lead a normal life. It mainly occurs due to mutations in the genes.
Depending on the severity and age of onset, Cockayne syndrome is classified into three types, out of which type II is the most severe. In severe cases of Cockayne syndrome, extreme sensitivity to light is observed; even mild exposure to sunlight can cause severe blisters in affected individuals.
According to studies, there are one to two cases in the million population. There is no proper treatment available for this condition yet. The primary treatment protocol involves supportive measures. The prognosis of this condition depends on the severity of the disease. The life expectancy is not above 50 years in this condition.
How Is Cockayne Syndrome Classified?
Cockayne Syndrome is classified mainly on the age of onset and disease severity. This classification also determines the life span of the affected individuals. The three types of Cockayne syndrome are:
Type I – This is the moderate or classic form of Cockayne syndrome. It is usually present in early childhood, around one to two years. The symptoms appear after the intrauterine growth and development. After the onset of the disease, the growth is very slow.
Type 2 – This is the most severe form of Cockayne syndrome. It is also known as cerebro-oculo-facial-skeletal syndrome. This form is present at birth, and it can affect intrauterine growth and development. Brain development does not happen in this form.
Type 3 – It is the milder form of Cockayne syndrome. Considerable growth and mental development can occur in this case. The symptoms start appearing only after two years of age. As the individual grows, symptoms may worsen.
What Are the Clinical Features of Cockayne Syndrome?
The severity of symptoms varies in each type of Cockayne syndrome. The main clinical features include:
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Photosensitivity – In some cases, sunburn can occur even with mild sunlight exposure.
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Microcephaly – The size of the head is very small.
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Delay in growth.
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Short stature.
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Kyphosis (hunch back).
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Thin nose and large ears.
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Minimal weight gain due to loss of subcutaneous tissue.
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Vision impairment.
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Dental problems.
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Wrinkling of the skin due to premature greying.
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Muscle wasting.
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Abnormal gait.
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Lack of coordination.
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Abnormal speech.
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Mental retardation.
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Hormonal issues.
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Kidney problems.
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Decreased sweating.
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Cataracts.
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Facial rashes.
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Hair anomalies.
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Brittle nails.
The severity of the above-mentioned clinical features is extreme in type II Cockayne syndrome. Severe neurological issues may lead to seizures, lack of urination control, etc., in this type. There will be growth failure at birth in type II Cockayne syndrome.
What Is the Etiology of Cockayne Syndrome?
It is an autosomal recessive disorder (the disorder that occurs due to an unhealthy gene's expression). It is mainly due to the mutations in the gene. Due to mutations in DNA (deoxyribonucleic acid), the cells become sensitive to light. There can also be decreased DNA and RNA (ribonucleic acid) synthesis. All these factors gradually contribute to the symptoms presented by the Cockayne syndrome.
What Is the Prognosis of Cockayne Syndrome?
Prognosis varies depending on the type of Cockayne syndrome. In type I, the life expectancy is approximately 10 years to 20 years approximately. In type II, the lifespan is up to seven years. Type III is the least severe form, and the affected individuals can have a lifespan of 40 years to 50 years. There is a slow progression of diseases in type III.
What Are the Complications of Cockayne Syndrome?
The complications of Cockayne syndrome include an increase in blood pressure (hypertension), skin cancer, dental problems, kidney problems, cardiac problems like atherosclerosis in younger age, gastroesophageal reflux in babies causing difficulty in feeding, lack of control over urination, difficulty in walking, difficulty in processing thoughts, and lack of learning skills. The affected individuals have a life-threatening reaction to Metronidazole. It can cause liver failure in affected individuals. So the use of Metronidazole is contradictory in these patients.
How Is Cockayne Syndrome Diagnosed?
By clinical examination, most of the features of Cockayne syndrome can be identified. It can be confirmed with genetic testing. Prenatal diagnosis can also be made if suspected. Laboratory studies like skeletal radiography, endocrinologic tests, etc., can help exclude other diseases similar to this. Computed tomography (CT) and magnetic resonance imaging (MRI) can be done for the disease's neurological problems.
What Are the Differential Diagnoses of Cockayne Syndrome?
Most of the mitochondrial diseases that exhibit clinical features of Cockayne syndrome can be the differential diagnoses of Cockayne syndrome. These include UV (ultraviolet) sensitive syndrome, Werner syndrome, Bloom syndrome, xeroderma pigmentosum, etc.
What Is the Treatment for Cockayne Syndrome?
There is no treatment for Cockayne syndrome. The main aim in providing treatment for the patients includes reducing the severity of the disease and managing the complications.
Some general measures have to be taken by the patients. These include eating nutritious food, sun protection, using sunscreen while going out, and physiotherapy. Metronidazole should be avoided in these patients.
For the visual problems, affected individuals must take the help of experts. Cochlear implantation can be done to minimize auditory impairment. For all the complications, treatment is given under the guidance of experts like neurologists, dentists, ophthalmologists, etc., however, only symptomatic treatment can be given, and there is no cure for this condition.
Conclusion:
Cockayne syndrome is a life-threatening condition. It is challenging to survive this disease. By taking proper measures, at least the severity of the disease can be controlled. Parents of the affected children should be well aware of the precautions that need to be followed.
