Genotype–phenotype correlations with autism spectrum disorder-related traits in Noonan syndrome and Noonan syndrome with multiple lentigines: a cross-sectional study
PTPN11-linked Noonan syndrome brings out the strongest autism-like social and repetitive features—so get the gene report and tailor early ABA.
01Research in Context
What this study did
McGhee et al. (2025) looked at kids with Noonan syndrome and Noonan syndrome with multiple lentigines. They wanted to know if the exact gene change behind the syndrome shapes autism-like traits.
They split the kids by gene: PTPN11 versus other NS genes. Then they compared each group to same-age peers without the syndrome.
What they found
Kids who carried a PTPN11 mutation scored highest on social-communication problems and repetitive behaviors. The more the mutation turned up the SHP2 protein, the tighter the kid's play and routines became.
Both NS groups showed more emotional problems than controls, but the PTPN11 group stood out.
How this fits with other research
de Leeuw et al. (2024) saw the same pattern in 16p11.2 CNV kids: big social-communication gaps and externalizing behaviors. Both studies say, 'Screen early and plan strong supports.'
Garg et al. (2015) looked at another RAS-pathway syndrome, NF1. They found milder repetitive behaviors, the opposite of McGhee's PTPN11 spike. The difference is likely method: Shruti used broad ASD criteria while McGhee zeroed in on RRB scales.
Smith et al. (2022) added that 16p11.2 kids also have sensory-registration woes. Taken together, genotype-first papers keep showing that spelling out the exact gene sharpens your picture of what the child needs.
Why it matters
If you serve a child with Noonan syndrome, ask the medical team for the genetic report. When you see PTPN11, expect stronger social-communication and repetitive-behavior challenges and start ABA targets there. Early, intensive focus on flexible play and joint attention may head off later emotional problems.
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02At a glance
03Original abstract
Noonan syndrome (NS) and Noonan syndrome with multiple lentigines (NSML) are neurodevelopmental conditions caused by genetic variants leading to upregulated signaling in the RAS-MAPK pathway. While previous research has focused on genetic variability in cognitive and cardiac phenotypes, behavioral phenotypes, and their correlations across genetic variants and within the PTPN11 gene remain poorly characterized. This study included 121 individuals with NS (PTPN11: 88, SOS1: 18, RAF1: 6, KRAS: 2, RIT1: 3, NRAS: 2, LZTR1: 2, SOS2: 1) and seven individuals with NSML (PTPN11), compared to age- and sex-matched typically developing (TD) (N = 71). Behavioral questionnaires assessed social responsiveness and ASD-related traits (using SRS-2), and emotional problems (using CBCL) to identify genetic variant-specific behavioral profiles. Biochemical profiling of SHP2 activity in PTPN11-associated NS variants examined genotype–phenotype relationships. Compared to TD individuals, those with PTPN11-associated NS, NSML, and SOS1-associated NS exhibited clinically elevated scores, indicating increased ASD-related behaviors, poorer social functioning, and heightened emotional problems. Genetic variant comparisons revealed that individuals with PTPN11-associated NS and NSML exhibited greater ASD-related challenges than those with RAF1. Individuals with NSML exhibit elevated attention problems compared to all other genetic groups. Logistic regression results suggested each one-unit increase in SHP2 fold activation for PTPN11-associated NS corresponded to a 64% higher likelihood of markedly elevated restricted and repetitive behaviors, suggesting genotype–phenotype links. Small sample sizes for rarer variants, leading to unequal group sizes across subgroups, with PTPN11 variants comprising most of the NS group. Future research should address these sampling constraints and conduct functional studies to clarify variant impacts. Longitudinal assessments could elucidate behavioral phenotype trajectories. This study underscores the importance of genetic variant-specific research to understand unique behavioral phenotypes in NS and NSML. Our findings indicate a higher risk for ASD-related symptoms in PTPN11-associated NS and NSML compared to other variants. Additionally, individuals with PTPN11-associated NS and higher SHP2 fold activation exhibited greater impairments in restricted and repetitive behaviors, suggesting SHP2 activation variations may contribute to phenotypic variability. By linking ASD-related symptoms to biochemical predictors in PTPN11-associated NS, this study may inform future targeted treatment approaches. The online version contains supplementary material available at 10.1186/s13229-025-00681-1.
Molecular Autism, 2025 · doi:10.1186/s13229-025-00681-1