Straight crease across palms in non-Down Syndrome individuals

(Inspired by this thread, for which I was researching Down syndrome. However, I couldn’t find a cite to substantiate what I wanted to post.)

One of several diagnostic features of Down Syndrome is the straight crease across the palms of the hands. As I have these creases, but am fairly sure I do not have Down Syndrome*, I’m curious as to how common they are in non-Down people and what other significance they might have.

*After all, I have multiple degrees and get invited to join Mensa after taking a GRE.

It’s called a simian crease. Palmar creases develop early in gestation, so often are a sign of an problem in development, but not always.

My pediatric pathology literature says it occurs in about 1% of normals.

Last time I was giving a lecture on Down syndrome to a small group of pathology residents, who had been joined by one grey-haired, bow-tied old attending physician, I showed a slide of the “simian crease” and mentioned this statistic. I was very glad i had done so when Dr. Bow Tie raised his hand to show his palm.

IIRC it’s constellations of the various features that made diagnosis of DS possible before chromosomal analysis.

i.e. While a simian crease, a large tongue, low-set ears, clinodactyly, a pronounced sandal gap and epicanthic folds can all be found in the general population, if three or more of the features occurred together in the same individual it made a diagnosis of Down Syndrome much, much more likely (but still not certain).

Also, with more mosaic cases (some cells have trisomy 23, some don’t, meaning the person may be very mildly affected) being picked up, they’ve changed the definition so that the possible IQ range for DS now goes up to 100 (it used to stop at 90).

Wow. I’m so glad you found a way to share that with us.

Uncalled for. I thought it was fair game to mention in the context. If it will make up for it, I do have a slight congenital defect, possibly correlated to the creases as picunurse’s post suggests.

Well as long you have something wrong with you I guess it’s Ok. Seriously I don’t really know why I reacted that way* and it was certainly uncalled for in GQ. So please accept my apologies.

  • Probably because Mensa wouldn’t have me as a janitor.

I have the straight creases, and no known defects.

Don’t forget the excess nuchal skin.

It’s the first thing they’re able to look for on ultrasound.

article with ultrasound photo of fetus

Small nitpick:

Down’s Syndrome is trisomy 21 and not trisomy 23 …

Carry on



Nitpicking my own posting, I should have used the preferred nomenclature for the condition :
Down Syndrome.


She didn’t say it was.
She said:

Mosaic defects also have simian creases. They also may look like they have Down’s. The difference is determined by genetic testing.