PHIP-related disorder, also known as Chung-Jansen syndrome, is a rare condition caused by a change in the pleckstrin homology domain-interacting protein (PHIP) gene. The most common signs and symptoms, include mild to severe learning problems, behavior problems, and a tendency toward being overweight. PHIP-related disorder is an autosomal dominant condition. This means that a person with the disorder has a 1 in 2 or 50% chance of passing the condition to each child.

Many people with PHIP-related disorder have mild to severe intellectual disability. People with the disorder who did not have intellectual disability, often have speech problems, global developmental delays in early childhood, and learning problems.

Problems with behavior are common. People with PHIP-related disorder and the following behavioral conditions have been reported:

• Attention Deficit Hyperactivity Disorder (ADHD)
• Features of autism
• Problems with impulse control
• Aggressive behavior
• Mood disorder
• Anxiety

In addition to learning and behavior problems, a tendency toward being overweight is common among people with PHIP-realted disorder.

People with PHIP-related disorder can have unique physical features, including:

• High forehead
• Full eyebrows with or without hair in between the brows
• Upturned nose with thick nostrils
• Long spacing between the nose and upper lip
• Thin lips
• Large ears
• Thick helices and earlobes
• Tapered fingers
• Curved pinky finger
• Slight webbing between the second and third toes
• Urogenital problems
• Vision problems
• Differences in skin pigmentation
• Fatigue