Prader-Labhart-Willi Syndrome (PLWS)

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Description

Prader-Willi syndrome (PWS) is a rare genetic disorder that affects many parts of the body. It is characterized by a complex set of symptoms, including:

• Delayed development: Children with PWS often experience delays in reaching developmental milestones, such as sitting, crawling, and walking.
• Feeding difficulties: In infancy, babies with PWS may have weak sucking and feeding problems.
• Muscle weakness: PWS can lead to hypotonia, or weak muscles, which can impact motor skills.
• Obesity: As children with PWS grow, they develop an insatiable appetite and a tendency toward obesity.
• Behavioral and cognitive challenges: People with PWS can experience intellectual disabilities, learning difficulties, and behavioral issues such as temper tantrums, stubbornness, and obsessive-compulsive behaviors.
• Other features: PWS can also be associated with distinctive facial features, short stature, and sleep disturbances.

Genes Involved

Genes Involved:

• SNRPN: This gene is essential for normal brain development and function.
• NDN: This gene plays a role in regulating appetite and energy metabolism.
• MAGEL2: This gene is involved in growth and development.
• Other genes: Several other genes located in the 15q11-q13 region can also be involved in PWS.

Recognizing the Signs and Symptoms

Recognizing the Signs and Symptoms:

• Infancy:
  • Poor feeding and slow weight gain
  • Weak muscle tone (hypotonia)
  • Delayed development (rolling over, sitting up, crawling)
• Early Childhood:
  • Short stature
  • Small hands and feet
  • Obvious feeding difficulties and excessive eating
  • Behavioral issues (temper tantrums, stubbornness)
  • Learning difficulties
• Adolescence and Adulthood:
  • Persistent obesity
  • Sleep apnea
  • Diabetes
  • Osteoporosis
  • Behavioral problems (obsessive-compulsive behavior, anxiety)

Causes

Causes:

Prader-Willi syndrome is caused by a genetic defect in a region of chromosome 15. The most common cause is a deletion of a specific section of the chromosome. In other cases, the syndrome can result from uniparental disomy (UPD), where a child inherits two copies of chromosome 15 from one parent and none from the other parent. The cause of PWS is often not known and may vary from case to case.

Inheritance/recurrence risk

Inheritance or Recurrence Risk:

• PWS is not inherited in the typical sense. It‘s typically a spontaneous event.
• However, the risk of having a child with PWS is slightly higher if a parent already has a child with the syndrome.
• The exact recurrence risk is difficult to predict and depends on the specific genetic mechanism causing PWS in the family.