Prader Willi syndrome is the condition that develops when some of the genes in chromosome 15 are deleted. The father’s copy of chromosome 15 is generally affected and causes a wide array of physical, mental, medical and behavioral problems. The condition likewise causes significant growth, motor and developmental delays. Those who are affected also have impaired intelligence and speech problems. Despite poor growth during infancy, children with the disorder grow unusually obese which accounts for most cases of childhood obesity.
Having a child born with Prader Willi Syndrome can be very frustrating, especially because the condition is untreatable. Treatment or management of the condition focuses more on supportive care to improve the overall quality of life of the patient as well as to prevent secondary complications from happening. It targets the dietary, physical, mental, educational, behavioral and medical needs of the patient. A team of doctors will work together to design the most appropriate treatment plan.
Causes of Prader Willi Syndrome
Problems associated with the syndrome have long existed. However, the condition was only recognized in the medical community in 1956 through the Swedish doctors, Andrea Prader and Heinrich Willi, after describing 9 children who all had the hallmark symptoms of the disorder, namely growth, developmental, mental and behavioral deficiencies. Since then, the syndrome was named after them.
Extensive research has paved the way to understand the reason behind Prader Willi Syndrome. Scientists have discovered the involvement of some genes that cause the problems associated to PWS. These genes could have been deleted or structurally-altered in the long strand of chromosome 15. Scientists have identified two of them, namely, SnoRNA and OCA2. SnoRNA or small nucleolar RNAs instruct the production of certain molecules that will control the RNA molecules. Their absence causes much of the problems associated with PWS. Meanwhile, the OCA2 gene is important in determining the color of the hair, skin and eyes. Their absence results in the unusual skin and hair color of PWS patients.
Development of Prader Willi Syndrome
PWS develops when an error occurs during cell division or if the sperm cell is defective. Each parent gives one copy of their chromosome 15 to their child. However, there are some problems to the contributed copy from the father and some of the genes could be:
The child may not totally have his or her father’s copy of chromosome 15 and have two copies of chromosome 15 from his or her mother instead.
The child may have inherited his or her father’s copy of chromosome 15 but some of the genes in it have been deleted or are lacking which deactivates the father’s copy of chromosome 15.
- Altered or translocated
The genes in chromosome 15 inherited from the father could be translocated. Genetic translocation could deactivate the father’s copy of chromosome 15.
PWS affects 1 in 12 to 15 thousand births regardless of gender and race. Genetic deletion in chromosome 15 accounts for majority of PWS cases, while 30% occur due to the complete absence of the paternal chromosome 15. A relatively rare and small percentage of PWS is a result of genetic translocation. Most people affected by Prader Willi Syndrome don’t have any family history of the syndrome; so PWS occurs randomly. Still, a few have inherited the defective gene from the parents.
Prader Willi Syndrome symptoms
Whether the genes involved are missing or defective, these have a huge effect on the hypothalamus – the portion of the brain that controls hunger and production of essential hormones for various bodily processes and development. With a malfunctioning hypothalamus, a lot of bodily processes including growth and development, temperature control, hunger, emotions and fertility, to name a few, are severely affected. This causes wide array of problems such as:
- Narrow forehead, almond-shaped eyes, triangular mouth, short stature and unusually fair skin and light colored hair.
- Low muscle tone, weak cry, failure to thrive, severe exhaustion and unresponsiveness during infancy.
- Delayed motor development during infancy, such as sitting and walking, as well as eye coordination.
- Delayed puberty due underdeveloped genitals because of hormonal imbalance which further leads to infertility.
- Hormonal imbalance also causes unusual food craving and behavior resulting to childhood obesity.
- Mild to moderate intellectual disability and speech and language deficits.
- Behavioral problems, sleeping disorders and compulsive behaviors are manifested from childhood to adulthood.
The affected individual is born with the syndrome but the problems are usually detected within the first year. The symptoms become more defined from the 2nd year onwards, and PWS is said to be in its second stage.
Prader Willi Syndrome life expectancy
A patient with Prader Willi Syndrome can lead a normal life only IF he or she manages to bring her weight in control. Since food cravings are a major symptom, it is important to follow proper diet, exercise and stay as fit as possible. The life expectancy of Prader Willi Syndrome is affected if a person continues to overeat and does not keep weight in check.
What does the future hold for Prader Willi Syndrome patients?
Children born with PWS can do better in life if the condition is detected and treated early. Treatment aims to address growth and developmental problems during infancy, delayed mental development and obesity during childhood, as well as behavioral and medical problems during adolescence.
Prader Willi Syndrome Pictures