Prader-Willi Syndrome

Symptoms that may be present from birth include:

• Poor muscle tone. A main sign during infancy is poor muscle tone, also known as hypotonia. Babies may rest with their elbows and knees loosely extended instead of fixed. They also may feel floppy or like rag dolls when they’re held.
• Distinct facial features. Babies may be born with almond-shaped eyes, a narrowing of the head at the temples, a turned-down mouth and a thin upper lip.
• Poor sucking reflex. Infants may have a poor sucking reflex because they have less muscle tone. Poor sucking makes feeding hard and can make it less likely they’ll gain weight at the expected rate.
• Generally poor responsiveness. A baby may seem very tired, respond poorly to stimulation, have a hard time waking up or weakly cry.
• Underdeveloped genitals. Males may have a small penis and scrotum. The testicles may be small or not descend from the abdomen into the scrotum. This is known as cryptorchidism. In females, the clitoris and labia may be small.

Other features of Prader-Willi syndrome appear when a child is very young and continue for life, including:

• Food craving and weight gain. A classic sign of Prader-Willi syndrome is a craving for food all the time, starting in early childhood. Being hungry all the time leads to eating often and eating large portions. This leads to quick weight gain. Unusual food-seeking behaviors, such as hoarding food, or eating frozen food or garbage, may occur.
• Underdeveloped sex organs. A condition called hypogonadism occurs when sex organs — testes in males and ovaries in females — produce little or no sex hormones. This leads to sex organs that don’t develop fully and incomplete or delayed puberty. Nearly all people with Prader-Willi syndrome aren’t able to get pregnant. Without treatment, females may not start their menstrual period until their 30s, or they may never have a period. Males may not have much facial hair, and their voices may never fully deepen.
• Poor growth and physical development. Not making enough growth hormone can shorten adult height and lead to low muscle mass and high body fat. Other endocrine problems may include not making enough thyroid hormone, also known as hypothyroidism. Another endocrine problem is central adrenal insufficiency, which keeps the body from responding properly to stress or infections.
• Having a hard time thinking, solving problems and learning. A common feature of Prader-Willi syndrome is having mild to moderate problems thinking, reasoning and problem-solving. This is called cognitive impairment. Even children and adults without cognitive impairment may have learning disabilities.
• Delayed motor skills. Toddlers with Prader-Willi syndrome often reach milestones in physical movement, such as sitting up or walking, later than other children.
• Speech problems. Speech often is delayed. Having a hard time choosing words and speaking clearly may continue as an adult.
• Behavioral problems. At times, children and adults may be very stubborn, angry, controlling or manipulative. They may throw temper tantrums, especially when denied food. They may not accept changes in routine. Also, they may start to show obsessive-compulsive or repetitive behaviors, or both. Other mental health conditions, such as anxiety and skin picking, may occur.
• Sleep conditions. Children and adults with Prader-Willi syndrome may have sleep conditions, including disruptions of the typical sleep cycle. They also may have sleep apnea, which is when breathing pauses during sleep. These conditions can make them very sleepy during the day and worsen behavior problems.
• Other symptoms. These symptoms may include small hands and feet, and curvature of the spine, also known as scoliosis. They also may have hip problems, less saliva flow, dental problems, and nearsightedness and other vision problems. Other symptoms include a lack of pigment, also known as hypopigmentation, which causes hair, eyes and skin to be pale. They also may have problems controlling their body temperature. They may be able to handle more pain than the average person.