The symptoms of Prader-Willi syndrome include low muscle tone, a noticeably narrow forehead, eyes that are amygdaloid or almond-like in shape, and a distinctive mouth characterized by a thin upper lip and a down-turned shape, notes Mayo Clinic. Other symptoms include an insatiable desire for food, leading to obesity.
Those with Prader-Willi syndrome, a genetic disorder, often have lighter hair and skin than their family members as well as smaller feet and hands, according to Mayo Clinic. Many also suffer from scoliosis and vision disorders such as myopia. In infants with Prader-Willi syndrome, vision problems may present themselves as a wandering or lazy eye. Hypogonadism is another common symptom of Prader-Willi syndrome and is characterized by underdeveloped reproductive organs, delayed onset or lack of menstruation, and infertility. Those with the syndrome may not develop fully at puberty.
Prader-Willi syndrome can also present a number of behavioral symptoms, including uncontrollable anger, intractability, an inability to adapt to change, and obsessive-compulsive behaviors. Cognitive symptoms such as impaired reasoning and the inability to solve problems are often associated with Prader-Willi syndrome as well. Infants with the syndrome typically develop motor skills later than their peers. Sleep disorders such as sleep apnea are also a common symptom of the syndrome, with many also suffering from excessive daytime sleepiness as a result of the chronic disruption to their sleep cycle.