PGR - 1 Average Intelligence with Rare Genetic Mutation Associated with Intellectual Disability.

OBJECTIVE: Chung-Jansen syndrome is caused by haploinsufficiency of pleckstrin homology domain interacting protein (PHIP). Patients identified with PHIP typically present with intellectual disability, learning disorder, atypical social behavior, facial dysmorphism and obesity. Common co-occurring clinical conditions include attention deficit hyperactivity disorder (ADHD), anxiety and/or depression, and autism spectrum disorder (ASD). Neurocognitive functioning is notable for a leftward shift, presenting with a relative strength in language comprehension and weakness in nonverbal ability.

METHOD: This is a 9-year-old female with an atypical PHIP mutation. The patient was born full-term. The pregnancy and delivery were uncomplicated (birth weight: 3572 grams). The PHIP mutation was identified in December 2020. Genetic testing was conducted due to developmental delay, ADHD, obesity, abnormal motor functioning, learning disability, and somatic complaints.

RESULTS: Neuropsychological testing indicated average intellectual functioning (FSIQ = 94). There were strengths in verbal comprehension (VCI = 116), verbal learning, and reading, with relative weaknesses in non-verbal ability (NVI = 83), non-verbal learning, and math. Scores on measures of social perception (Affect Recognition, Theory of Mind) were consistent with verbal ability.

CONCLUSIONS: This is an important case in understanding Chung-Jansen syndrome and PHIP. Most key clinical features are present (e.g., ADHD, atypical social behavior, obesity), albeit at a higher level of intellectual functioning. PHIP has typically been associated with intellectual disability; the present case suggests that the clinical pattern is present with higher functioning individuals as well. Genetic testing may be warranted when evaluating individuals with average cognitive functioning and relative strengths in verbal ability along with co-occurring atypical social behavior, ADHD, and obesity.