Restricted growth, sometimes known as dwarfism, is a condition characterised by unusually short height.
There are 2 main types of
restricted growth:
- proportionate short stature (PSS) – a general lack of growth in the body, arms and legs
- disproportionate short stature (DSS) – where the arms and legs are particularly short
Restricted growth (dwarfism)
So precious how that google knowledge works - pity you stopped reading where you did. The very next sentence:
"As well as being short, some people with restricted growth also have other physical problems, such as bowed legs or an unusually curved spine."
And a bit further down, re: DSS:
Causes of DSS
A
rare genetic condition called achondroplasia is the most common cause of DSS.
It causes poor bone growth, resulting in short upper arms and thighs.
And were you to follow the link provided, you might have seen:
People with Achondroplasia have a range of characteristics including:
- A near normal trunk length with shorter arms and legs
- A large head with prominent forehead and flattened bridge of the nose
- An increased curvature of the lower spine (lumbar lordosis)
- Bowing of the lower legs
- Possible crowded teeth
- Short, broad feet and hands with separation between middle and ring fingers (the ‘trident’ hand)
- Exceptionally flexible joints
- Babies with Achondroplasia may develop motor skills and mobility more slowly than normal because of the combination of a heavier head and shorter arms and legs, but ultimately development is within the expected normal range.
Some medical complications associated with Achondroplasia are listed below. Note: most of these affect only a minority of people with the condition.
- Glue ear / hearing impairment
- Breathing problems in young children
- Hydrocephalus
- Spinal stenosis leading to compression of nerves to the limbs
- Joint problems due to leg bowing
Achondroplasia is due to a change in the gene that codes for Fibroblast Growth Factor Receptor 3. (FGFR3). In almost all cases the single base change is exactly the same. The estimated prevalence is 1 in 25,000.
But you didn't.
Hmmm....
Achondroplasia.... where have I heard that before.. Oh, yes -
right here:
"There is a condition called achondroplasia - most people know it as dwarfism.
Dwarfism is characterized by such things as disproportionate limb length, characteristic facial features, reduced interphalageal joint number, etc.
Tell us - which of those was created first?
The shortened limbs? The shorter muscles and blood vessels need for shorter bones?
The facial features?"
All of that from a single point mutation .
But you are utterly perplexed about the relationship between skull and brain size.... Hmmm....
Isn't it funny how ALL creatures with skulls, regardless of brain size, just happen to have skulls that their brains fit into...
But you are having this totally hard time understanding why when it comes to humans... Becaus eyou are ignorant of biology and a very disingenuous 'debater.'
Again, you have made a stupid parallel between skull and brain with limbs and arteries
in genetic disorders,
It would be so awesome if you actually had sufficient relevant education and knowledge in these areas - you simply cannot grasp the relevance of the analogy to achondroplasia I have been presenting to you.
One last time, then I am putting you on ignore for your repeated insolence -
In achondroplasia, a single point mutation alters development of the limbs and face such that they exhibit disproportionate growth, just like your link indicated. Had you read it.
The mutations that allowed for increased neocortical also allowed for the requisite cranial expansion.
That is how growth and development works.
Wow..... Those brains look TOTALLY different....
Of course they're different, otherwise your head will be like a monkey, are you?
Am I what?
Tell us all, with your expertise in brain anatomy, how, exactly, the human and chimp brains you pasted are different.
Right. I've only been teaching things like anatomy and evolution at the college level for decades. What do I know about this...
Many teachers and many doctors were stupid, so what
Coming from a person that has a hard time putting words together into recognizable sentences, and who has such a hard time understanding analogies and the like, that is rich. Thank you so much for your Christian humility.
Great comeback!
But do go on and explain how the skull has to get larger via evolution first, then later, the brain evolves to fill it up.
By plan and design, by science and not luck
Great explanation! I'm sure that level of detail would awe a 3rd grader.
I did - that is how I came to the most obvious conclusion - you do not do a very good job hiding the obvious fact that you do not understand anything about evolution.
Or biology.
It's really sad that you're a teacher, but good that you weren't a doctor otherwise many will
lose their life.
Oh boy! You really got me with your clever wit!
Onto ignore you go. The fewer trolls that clog my view the better.