Association of BDNF levels with IQ: comparison of S100B and BDNF levels in typically developing children and subjects with neurologically normal nonsyndromic intellectual disability.
Lower blood BDNF links to nonsyndromic ID and weaker performance IQ, giving a new clue behind cognitive and activity gaps.
01Research in Context
What this study did
Adams et al. (2021) drew blood from two groups of children. One group had nonsyndromic intellectual disability. The other group was neurotypical.
They measured two proteins in the blood: BDNF and S100B. Then they compared the levels to IQ scores.
What they found
Children with ID had lower BDNF than the control group. Higher BDNF went with better performance IQ in both groups.
S100B levels looked the same in both groups. So BDNF, not S100B, tracked with thinking skills.
How this fits with other research
Friedling et al. (1979) showed that a quick free-play score also predicts IQ in disturbed kids. Their play test is cheaper than a blood draw.
Van Hanegem et al. (2014) found kids with ID are more often overweight and move less. Low BDNF may be one hidden reason, because BDNF helps brain circuits that drive movement.
Together the papers paint the same picture: kids with ID often show lower activity, poorer play, and now lower BDNF. The new data add a possible body-chemistry clue, not a contradiction.
Why it matters
You can’t test BDNF in clinic today, but you can watch play and activity. If a child looks sluggish or plays in simple loops, boost movement sessions and track change. The blood hint tells us the brain may reward that work more than we see on the surface.
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02At a glance
03Original abstract
BACKGROUND: Brain-derived neurotrophic factor (BDNF) and S100B are reported to play an important role in neurodevelopment and may contribute to developmental pathogenesis in neuropsychiatric diseases. In this study, we aimed to examine the possible roles of BDNF and S100B in the pathogenesis of nonsyndromic intellectual disability (NS-ID) and their relationship with cognitive performance. METHODS: Thirty-three patients with intellectual disability (ID) and 30 typically developing children were compared. BDNF and S100B serum levels were measured with ELISA. The Wechsler Intelligence Scale for Children-Revised Short form (WISC-R) and Leiter intelligence test were administered to determine the intelligence levels of subjects. Leiter intelligence test was applied to 10 participants (30.31%) in the ID group because they had speech and communication problems. All other participants underwent WISC-R. RESULTS: Brain-derived neurotrophic factor levels were found to be significantly low in the patient group (mean ± SD, 67.43 ± 29.74 pg/mL) compared with the control group (94.67 ± 32.55 pg/mL) (P = 0.002). When S100B is assessed, there was no significant difference found between the patient group (335.05 ± 279.89 pg/mL) and control group (295.30 ± 146.55 pg/mL) (P = 0.901). There was a significant positive correlation between BDNF and performance IQ (r = 0.424 and P = 0.001) in all participants. In addition, positive correlations were found between BDNF levels and initiating speech time (r = -0.369 and P = 0.003). CONCLUSIONS: Brain-derived neurotrophic factor deficiency is proposed to have a possible role in the pathology of NS-ID. High BDNF levels may be associated with better cognitive performance.
Journal of intellectual disability research : JIDR, 2021 · doi:10.1111/jir.12896