The Curious Case of the Stubby Thumb

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Photo: A BDD thumb (left) and a normal thumb (right)

by Rosa Lin/Medill News Service

“What happened to your thumb?”

“Did you accidentally smash it in the door?”

A thumb was outstretched in the circle of sixth-graders. It had a most peculiar shape, being relatively thin and normal near the base, and then suddenly capped off with a bulbous, short tip, reminiscent of a slightly flattened pearl onion.

The thumb belonged to 10-year old me.  And I was showing it off proudly among my bemused friends.

“See, the other one's like this too!” I stretched out its equally short and bulbous sister. Everyone gaped, laughed, and held the thumb up for inspection.

“You must've bitten your fingernails too often when you were little!”

“Did you jam your thumb playing basketball?”

Why, no, I was born this way. If you're like me, you probably fielded these questions in your youth and wondered whether anybody else in the world has thumbs like yours.

Wonder no more – these thumbs are known in scientific circles as brachydactyly type D, a type of thumb characterized by a shortened distal phalanx (the bone at the tip of the digit) – and we are about to plumb the history, prevalence, myths and genetic basis behind these thumbs.

Most people have a straight, upright thumb, with a nail bed equal to or longer than the nails on their fingers. Some people have a “hitchhiker's thumb” where the tip can bend back almost 90 degrees. Finally, a few people – from 0.10 to 3 percent of a population – have a shortened thumb, a feature colloquially known as club thumb, stub thumb, toe thumb, potter's thumb, hammer thumb and most unappealingly, murderer’s thumb. Fortunately the thumb has been christened neutrally by scientists as brachydactyly type D, so henceforth we shall stick with the designation BDD.

BDD was first characterized by fortune tellers practicing palmistry. According to Angelfire.com's page on Indian palmistry:

"The Murderer's Thumb Unveiled - The clubbed thumb was traditionally called the 'murderer's thumb' denoting the powerful temper of those who carried it. This thumb has a short first phalange (section) and is broad. The tip of the thumb is fleshy and the thumbnail is short and broad. According to those who know, people with clubbed thumbs [however] are strong willed and can control their emotions."

Such a description is rather more palatable than Palmistrylines.com's take:

"This thumb is in a shape of a club. People possessing this type of thumb are animalistic in nature and thought system. They bear brutality of Elementary type. They can harm or murder out of callousness. They lack premeditation and depth."

Ouch! This leads the meeker among the BDD carriers to wonder: why such a dark reputation among chirologists? For the record, chirologists are fortunetellers.

“When these [traits] started getting studied in the late 19th century … there was a push to link [physiological] traits with personality traits. There's no real scientific connection between BDD and any personality trait though,” said Dr. Nathaniel H. Robin, an active clinical genetics practitioner and professor at University of Alabama at Birmingham, who authored a paper on BDD.

BDD is so named because it is one of many traits of brachydactyly, the term given for shortened fingers and toes due to underdeveloped bones in hands and feet. For example, there is brachydactyly type A, where middle phalanges of one, several, or all of the fingers and/or toes are shortened; brachydactyly type B, where distal phalanges and nails of the fingers and/or toes are small or absent; and so forth up to type E. Usually brachydactyly is an isolated trait, meaning that it is not associated with other medical conditions and is generally harmless.

Contrary to what many people with BDD think, BDD “is a fairly common trait,” Robin said. It stays in the population because “it's a benign variant,” meaning it is neither advantageous nor detrimental to those that express the trait.

According to "Abnormal Skeletal Phenotypes," published in 2005 by Alessandro Castriota-Scanderbeg and Bruno Dallapiccola, two prominent radiologists, BDD occurs in 0.4 percent of whites and 0.1 percent of blacks in the United States, with a higher incidence in Israel (1.6 percent of Jews, 3 percent of Arabs) and Japan. In three-quarters of cases, BDD occurs bilaterally, which means it appears on both thumbs, while in the rest of the cases it only appears on one thumb, with the other thumb normal.

There is also a skew among genders. The pioneering human geneticist Julia Bell found in a 1951 study that 60 percent of those affected with BDD were female, while 40 percent were male. The geneticist Robert Stecher confirmed the preponderance for females in a 1957 study. The reason for this may be due to incomplete penetrance, a genetic term that means that a trait fails to express itself even though a person carries the necessary genes. In the BDD case, there is evidence to suggest that the trait has complete penetrance in females and incomplete penetrance in males. BDD is also an autosomal dominant gene, which means a person only needs to inherit it from one parent in order to express the trait.

In the past 10 years, scientists have been able to gain more insight into the genetic basis of BDD. In a 2003 study published in The American Journal of Human Genetics, researchers reported that two mutations in the gene HOXD13 may contribute to BDD.

So who has this trait? One of its most famous carriers is Megan Fox, an actress starring in the "Transformers" movies. She carries the trait on only one thumb, signaling incomplete penetrance. Due to her profile as a celebrity, discovery of her BDD thumb was highly publicized. Russian author and Nobel laureate Alexander Solzhenitsyn is also purported to have at least one BDD thumb. Other people with the trait include: Malin Akerman (US actress), Tory Mussett (Australian actress), Ashley Lynn Cafagna (US actress), and Kristen van Der Noot (Germany DJ and model).

The most speculated of BDD carriers, however, is past European royalty. Despite valiant efforts, I did not find which royals exactly are implicated, so we shall briefly suspend any curiosity along those lines. The European royalty had higher than normal incidence of inbreeding due to a desire to keep their bloodlines “pure.” This resulted in any abnormality or mutation, such as hemophilia, reappearing in higher rates in descendents, instead of being flushed out by a set of significantly different genes. BDD is claimed by some to be a marker of descent from European royalty. However, as BDD occurs all around the world and is both the result of inheritance and random mutation, this, if true, would only apply to a small subset of those with BDD.

“I have no idea” if BDD is linked to European royalty, Robin said. “It may be true – I have no idea.”

At least I have an idea whether mine is linked to European royalty - I'm 100 percent East Asian!

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Comments

I also have BDD on both thumbs and hitchhiker's thumbs as well. My dad doesn't have them, but my granddad did, but my male cousin had stub big toes instead. My youngest lad is three and has shorter than normal thumbs (though not as stubby as mine), hitchhiker's thumbs, and stub big toes.

I had no idea there was a

I had no idea there was a name for my weird thumbs!  My Mom and her three sisters all had them, and all checked their babies for "fat" thumbs.  I assume either Grandma or Grandpa had them too.  My daughters do not have them--lucky for them!  Texting is a challenge with these thumbs!  I have to just hunt & peck.

I have two short thumbs.  The

I have two short thumbs.  The only difficulty I have had is as a Marine I had thumb safely selectors on my M-16 and 9mm pistol.  For my personal weapons I had a gun smith put on an extended safety selector.    

Yes!  Two-handed thumb

Yes!  Two-handed thumb texting is hard! But I'vejust graduated myself from vertical index finger to horizontal with BDD thumbs.  It is delicate, but can be learned.  Happy texting, fellow BBD people!

After 42 yes I finally have a

After 42 yes I finally have a name for my "dumb" tumb!  I only have one and it's my right one.  Neither or my children inherited it even though my sister in law has one.  I think mine comes from my dad's side as no one that I know of on my moms has it.  I think one of my toes may qualify as well as its really smaller than its mate.  Do any of you all notice that any of your fingernails really match their mates?  All of the fingernails on my right hand with my BDD thumb are bigger than the ones on my left. 

I also have a BDD club thumb.

I also have a BDD club thumb. I loved that you brought up the texting issue, it is a challenge!  I have always hated the look of that thumb as I think they are ugly. Thankful I only have one and that my only child, a son did not inherit it.

Hehe this is so strange i

Hehe this is so strange i thought i was the inly one!! Mine are on both of my thumbs, i never reeally show anyone so not alot of people kniw i have funny thunbs, guess thats why i thought they where normal. :)

i have bdd in both of my

i have bdd in both of my thumbs and in all of my toes. i recently had a baby and i got an email about traits you get from your father and that was one of them. my step brother has always called my thumbs disposable just because they are so tiny. 

I love my short thumbs! I own at thumb wars and video games with them! Plus, it helps me hold my chopsticks better.

I have one on my left hand

I have one on my left hand and i swear its the reason im a great artist also my friends never made fun of me just when we had a beer bong they'd yell for me to plug the tube with "my big thumb" lol. I only noticed i had it since high school 

I always thought that it is more 'prevalent' to male than female since the only people i've met with those thumbs were my grandad, my uncle, and my former boss. Now that I know Megan Fox also has it plus the fact, as you stated above, that actually it is more common in females, I'm glad that I'm not alone :) Thanx for the information

My mom had BDD on both thumbs - and also had hitchhiker's thumbs. As an adult she was privately rather proud of her thumbs; but she once told me when she met my dad she worried that he wouldn't like her because of her strange thumbs.

i have two of these thumbs I

i have two of these thumbs I'm 14 years old when people see them they laugh or either tell someone to look and they pic on me because of that. Some people think I get this from sucking my thumb which I dont. I don't like raising my hand in class caide of th . Now I know that I'm not the only one with these thumbs and can relate to other I know I'm not alone and I need to connect with people like me so kik me salenab4312 or snapchat salenabrockin 

I am 14 too and have two BDD

I am 14 too and have two BDD thumbs. I was relentlessly teased all through elementary school but I didn't care. I was so embarrassed to have my nails done by a friend or in a salon, but now that I've gotten over it I like my dumb thumbs! I am the only one in my extended family who has BDD, although my grandfather on my dad's side died before I was born, so maybe thats where I got it. Also, I am a red head and three of my friends who are redhead have BDD also! Not sure if there's a link there?

Salena you are not alone.

Salena you are not alone. Both of my thumbs are like that. I have really big, big toes also and very short stubby pinky toes. I'm sorry I don't have kik or Snapchat but I'll try to post a pic on here. I'm 34 and still get teased till this day about my thumbs but I always tell everyone I'm unique and your just jealous cause of it. The only thing I hate about my thumbs is I can't get fake nails put on. French manicures are really cute though with our kind of thumbs. Keep your head up and be proud of yourself.

I have two of these thumbs, but one is more "stubby" than the other one. I had never met anyone with thumbs that resembled mine, not even my parents so I thought it was a deformation. Then one day, I saw two people across a bar comparing thumbs, I jumped up and ran over and sure enough, they both had toe thumbs too! Since then I've met a couple more and finally, thanks to the Megan Fox hand-double stories, I found out that there is actually a name for it - AND it even has it's own facebook page! Thanks for all the information. :)

Great article! I have two clubbed thumbs, and am descended from English royalty on my mother's side. I have been able to trace my line right back to King John Lackland and his ancestors. Obviously, it is impossible to know for certain whether or not the trait is related to royalty, but I'd certainly like to think so. Gives me ammunition for all the haters. "Oooooh, what happened to your thumb? Does it hurt?" "No, it does not. But it does serve as a constant reminder that I have royal blood. Ha!"

Not to be a party pooper but

Not to be a party pooper but almost anyone of any European nationality is descended in some way from royalty or nobility. Think about it, if you're the king, you can pretty much do whatever (or who) you want. And yes, I do have "clubbed thumbs," too.

I am jamaican and i have too

I am jamaican and i have too stubbed thumbs. I was teased as a child for having the but over the years they have grown on me. Happy to known i'm not alone as i think. Now when i have a child i have an explanation and a name for it. Thank u . 

i have BDD thumbs and I'm

i have BDD thumbs and I'm Mexican. i am the only person in my immediate family who has this trait. My uncle and paternal grandmother have BDD thumbs. my grandmother is 90 % Mexican Indian. Iva always hated my thumbs. I hope to someday be proud of them. Haha

I'm also Mexican but have

I'm also Mexican but have Indian in my genes. Both of my thumbs have BDD. This gene had passed several generations and some of my siblings have them. Now my daughter has them too. I used to be embarrassed but not anymore,god made beautifully  and wonderfully  so I embrace what God gave me 

I am Dutch and have 2 of thse thumbs....I love them and all they are referred to as my shovel thumbs.... My sister has 2 as well .... It's up for debate. But mine are way cuter. She of course diss agrees :)

I have one thumb with BDD and one "normal" thumb. I came across this site as I have decided to look into the reason for this. I know one other person with this "trait"and have known him for about 17 years now. Strangly, he has told me on numerous occasions that I am of royal bloodline.

No way! I have one thumb like this. I accidentally got to this article...I never knew it was like a real condition with a name and that people actually studies it. I just figured it was just a little mistake of nature. I remember being a bit embarrassed about it when I was younger, but people hardly ever notice and I personally really could think of worse things you can have. I don't know anyone else in my family who has it, but there must be someone....maybe I just never noticed it. I'll look for it now I know that it's hereditary!

I am similar to you and it's

I am similar to you and it's good to know it's actually a genetic condition. I am female and Australian and also felt embarrassed by it growing up. I have one BDD thumb but one of my 3 brothers has 2 BDD thumbs. None of my other relatives that i know if have it. If I'm with new people I still tuck my BDD thumb under my fingers if my hand is resting somewhere visible.

Thanks so much for the article. BDD thumbs have been on my mind a lot lately as 2 of my employees and myself are proud owners of a pair each! This is among a staff of 8! Isn't that amazing. As a young girl I was teased and told that my thumbs indicated that I was mentally deficient. I can remember being in church trying to hide my thumbs from the priest when I took communion. As a seamstress and handcrafter I do find some of my detail work a challenge,but then feel great when I can accomplish beautiful tasks! Thanks for the article.

My two thumbs are like that, my maternal grandmother also had both thumbs, she used to tell me that one of her brothers had them. She was born in Spain.
I think that one of the Monaco's princesses, cannot remember if it is Caroline or Stephanie, has at least one, I have seen it in some close ups of her hands.
I really don't like my thumbs, most people have never seen them.

Mine are both like this and I too was tormented over my "spooners" as a child and teen. I used to try and hide my thumbs. Now I see that I am not a "freak" after all and I kinda like my thumbs. :)

I have them too on both and

I have them too on both and was teased in school. I am now 43 and still notice myself hiding them. I have two children and that was the first thing I checked when they were born. Neither of them got my thumbs. I was glad. Don't think I'll ever be OK with them!!!

I feel the same way. both my

I feel the same way. both my thumbs look like a big balled chicken leg.lol  and I always catch people looking and smirking. I try to grow my thumb nails a little but I just can't seem to get rid of my big toes for thumbs haha. but there are a lot of annoying people out there and you can't stop them all from laughing. so don't beat em, join em and laugh away. then go home and cry like me lol 

I'm Jewish and I have BDD on both thumbs, and a shortened bone in one of my big toes. Having it in only one foot made me very self conscience as a child, but now I've grown to like it for making me unique. People seem to notice my BDD frequently, but I only ever receive compliments on how cute my thumbs are. I think that my thumbs do have an advantage with typing because of the angle of my hands on the keyboard. One distinct and obvious disadvantage is that my thumbs don't reach as far as other people's thumbs, making some notes on musical instruments more difficult to play for me.

I have two matching clubbed thumbs and was mildly embarrassed by them when growing up and as a young adult but most people don't notice them. A Chinese friend called them my LUCKY THUMBS! My mother had two and I think her father did but I never met him and she was a little vague about telling me. From photos I suspect that one of my grandfather's brothers had them too. None of my four children inherited them nor my grandchildren. I searched the internet for the condition only recently and find it fascinating to read all this. Thank you!

Never knew it was a classified condition, but I have two proudly, very stubby thumbs. The last section is about half the length of a normal thumb, and like many others here, I have had to explain them many times. Thing that was funny for me is that I don't recall having to explain my thumbs as a child, but as I got older, people noticed them and asked about them.

My wife doesn't particularly care for my thumbs, but it's not like it stopped her from marrying me (9 years so far). However, when my daughter was born, the first thing she 'checked' on her was to see if she inherited my thumbs...she did not.

Lol, the first thing my

Lol, the first thing my husband did when our daughter was born is check her thumbs! So far she's escaped but she's only the first. I'm hoping at least one will inherit my thumbs ;)

I have one BDD thumb and

I have one BDD thumb and neither of my parents had BDD. I have two kids,a boy and a girl, my daughter also has one BDD thumb (opposite mine) and didn't really notice the development of hers until close to age five...she loves that she has a thumb just like mine!!

I've always been proud of my

I've always been proud of my unusual thumbs because they were just like my paternal grandmother's and paternal aunt's.  I also checked my son's thumbs when they were born!  Neither of them inherited my thumbs.  I've asked my cousins about their children's thumbs and there is one girl who has them.  I had no idea there were so many other people with these thumbs and that they had so many names for them!

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