Study – Genetics, Sleep & Toddler Temperament

I don’t know about you, but I function like a zombie on Xanax when I’m sleep-deprived; I’ve always been envious of those who survive (and thrive) on 4 hours of sleep per night.

So true I nearly cried... Until I realised I didn't have the energy to stimulate my tear ducts.

So true I nearly cried… Until I realised I didn’t have the energy to stimulate my tear ducts.

Researchers have taken this question of why some people are more affected by sleep deprivation than others to a whole new level.

In over 200 kids aged 6-36 months they compared:

  • A polymorphism in the serotonin transporter gene (serotonin is a neurotransmitter responsible for many muchness – but namely sleep, mood, appetite, memory, learning) against
  • A child’s susceptibility to changes in sleep duration as expressed by negative emotions and behavioural dysfunction (in simple terms – “Is your kid a nut job when they don’t get enough sleep?”)

Their methodology: “triallelic genotyping of 5-HTTLPR was performed by looking at SLC6A4 genotype, focusing on 5-HTTLPR including the SNP polymorphism rs23351.”

Sure, whatever you say.

After controlling for demographics and maternal depression (potential confounders) they found that kids with low-expressing genotypes were more likely to have negative emotions and behavioural dysregulation in the event of reduced sleep duration. Essentially it means that there are genetic markers of increased environmental sensitivity (and subsequent emotional development).

Nothing is simple anymore.

2015-11-06 13.20.53

Exhibit C “The Tired Child”. Yes yes, he DOES look like the child from The Exorcist .

So when your kid is tired and being a nut job (and other parents are looking at you disapprovingly despite having been in the EXACT SAME SITUATION themselves), instead of apologetically saying:

“He/she hasn’t had much sleep…”

You can now state with authority:

“He/she potentially has SNP polymorphism rs23351 and low-expressing 5-HTTLPR.”

That’ll shut ’em up.


Bouvette-Turcot AA, Pluess M, Bernier A, Pennestri MH, Levitan R, Sokolowski MB, Kennedy JL, Minde K, Steiner M, Pokhvisneva I, Meaney MJ,Gaudreau H; MAVAN research team. Effects of Genotype and Sleep on Temperament. Pediatrics. 2015 Oct;136(4):e914-21. doi: 10.1542/peds.2015-0080. Epub 2015 Sep 14.

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