Variability in neuropsychological functioning in patients with downstream RAS pathway mutations. Poster presented at the 47th Annual Meeting of the International Neuropsychological Society. New York, NY.

Abstract

Objective: Gene mutations within the Ras-mitogen-activated protein kinase (RAS-MAPK) signaling cascade have been associated with multiple genetic syndromes with varying degrees of neurocognitive impairment. Current research has focused on how specific molecular alterations in RAS pathway genes may predict the presence and severity of neurocognitive sequelae. Results from cohort studies suggest greater frequency of neurocognitive and adaptive impairment with more downstream mutations (i.e., Cesarini et al., 2009; Pierpont et al., 2010), with a high degree of variability noted across individuals with the mutations in the same gene (e.g., Pierpont et al., 2016). The aim of the current study was to examine the neurocognitive profiles of individuals with downstream RAS pathway mutations. Participants and Methods: Participants (ages 3-24) with MEK2 (n=3), BRAF (n=4), and KRAS (n=6) mutations were administered neurocognitive evaluations, including measures of nonverbal intellectual ability, receptive vocabulary, and adaptive functioning. Nonverbal reasoning (DAS-II & KBIT-2) and receptive vocabulary (PPVT-IV) scores were compared alongside overall parent-rated adaptive skills (Vineland-3). Results: More than half of the sample (54%) met criteria for intellectual disability, with significant neurocognitive variability among the remaining participants. Parent-rated adaptive functioning was generally higher in those patients whose verbal skills were relatively strong compared to nonverbal abilities. Further exploration of adaptive functioning skills indicated relative strengths in social skills for the majority of the current sample. Conclusions: While there was a high degree of variability across participants, patterns of cognitive and adaptive functioning emerged based on the specific gene mutation. The BRAF mutation was associated with a greater degree of neurocognitive impairment. Study findings may assist with guiding treatment planning and family-based interventions.