Epilepsy in a cohort of children with Noonan syndrome and related disorders.

Noonan syndrome (NS) and related disorders encompass a phenotypically heterogeneous group of conditions due to mutations in the Ras/Mitogen-activated protein kinase pathway. The main objective of this study was to assess the presence and characteristics of epilepsy in children and adolescents affected by NS and related disorders. The study included all the patients aged 5-21 years who had been diagnosed with NS or of one of three Noonan-like syndromes (i.e., cardio-facio-cutaneous syndrome, Noonan syndrome with multiple lentigines, and Noonan-like syndrome with loose anagen hair) at a university pediatric hospital. Clinical, EEGs, brain MRIs, and genotype data were extracted from the medical records, and follow-up telephone interviews were conducted to obtain updated information about epilepsy and its course. Out of a total of 75 patients (38 [50.7%] males, median age at assessment 12.0 years [q1 9.0-q3 17.0]; 61 [81.3%] with NS; and 14 [18.7%] with a Noonan-like syndrome), 13 (17.3%) had epilepsy, with median age at onset of 4.0 years (q1 2.0-q3 8.0, min 0.1-max 17.0). Epilepsy was more common among Noonan-like patients (50.0%) than in NS (9.8%, p < 0.001), and its presence was associated with neurodevelopmental delay (p < 0.001, OR 14.6 95% CI 3.6-59.4), cognitive impairment (p = 0.002, OR 11.2 95% CI 2.5-51.0), need for educational support (p < 0.001, OR 21.8, 95% CI 2.6-179.1), and lower adaptive functioning (median [q1-q3]: 54.0 [q1 40.0-q3 77.5] vs 97.0 [q1 76.5-q3 107.0] of the non-epileptic subgroup, p = 0.004). In 10 out of 13 cases (76.9%), the epilepsy outcome was good (i.e., seizure-free for more than 12 months with or without anti-seizure medication). CONCLUSION: Epilepsy was more common in NS than reported in the general population, with a significantly higher rate in Noonan-like syndromes. Epilepsy was associated with neurodevelopmental delay, cognitive impairment, and lower adaptive functioning. WHAT IS KNOWN: • Neurological abnormalities have been reported in NS and related disorders. • There is evidence of a phenotype-genotype relationship for neurological abnormalities. WHAT IS NEW: • Epilepsy was found to be more common in NS and related disorders than typically reported in the general population and associated with neurodevelopmental delay, cognitive, and functional impairment. • The Noonan-like phenotype had a higher frequency of epilepsy than typical NS.

Psychopathology and Adaptive Functioning in Children, Adolescents, and Young Adults with Noonan Syndrome.

OBJECTIVE: The objective of this study was to examine psychopathology and its impact on adaptive functioning in a sample of patients affected by Noonan syndrome (NS), a genetically heterogeneous condition with systemic manifestations. METHOD: Forty-two subjects affected by NS (23 males and 19 females), aged 5 to 21 years (mean 12.6 ± SD 5.1), were assessed for nonverbal cognitive abilities, with dimensional measures of psychopathology, adaptive functioning, and family quality of life. RESULTS: The nonverbal intelligence quotient (IQ) mean was 99.4 ± SD 22.2, with 3 subjects (8%, 95% confidence interval [CI], 1.6%-20.9%) showing cognitive impairment (IQ<70). The Parent Child Behavior Checklist (CBCL) total psychopathology score was in the clinical range in 10% of sample and borderline in another 10%. On the Conners' Parent Rating Scales, scores suggestive of attention-deficit/hyperactivity disorder (ADHD) were in the clinical range in 20%. On the autism quotient, autism spectrum disorder symptoms were reported in 10%. Higher scores on the Adaptive Behavioral Assessment System-Second Edition and on the World Health Organization Quality of Life (26 items) were associated with lower problems on the CBCL (r = -0.63, 95% CI, -0.78 to -0.40 and r = -0.48, 95% CI, -0.69 to -0.20, respectively). CONCLUSION: Psychopathology was common in patients with NS and negatively correlated with global functioning and family quality of life. Treatable psychopathology, such as ADHD, may constitute a treatment target for improving adaptive functioning.