One famous person was the inventor Charles Martin Hall who appeared to be in his 20s while almost 50 -- interestingly, he died at only 51 so his appearance may have not been indicative of overall health. I can't find any information about this fairly trivial aspect of his life online although I vaguely a recall a biography mentioning his appearance; not sure if it also mentioned any reason for it. I would guess that some hormonal or developmental disorders could indeed cause someone to appear child-like throughout their lives although such lives would not tend to be long. But is there any condition wherein a person develops normally but simply looks much, much younger than their chronological age in later adulthood?

EDIT: I recall that a semi-serious article about the character Tin Tin who (like many comic characters) remained youthful forever written by a doctor suggested that Tin Tin's appearance might have been due to a head injury. If so, not sure why that would affect ageing except I guess a serious injury could affect the pituitary?

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    Welcome to MedicalSciences.SE. This is an interesting hypothesis as there is a condition which produces the opposite effect and that is Progeria Oct 15 '18 at 10:50
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    Conditions that come to mind are described and taught as having signs that include "childlike facies", or "childlike features" (e.g., Williams syndrome, certain kinds of dwarfism and hypogonadism, and, I think i've heard the typical facies of Angelman syndrome described that way), but none of these involve "developing normally".
    – De Novo
    Oct 15 '18 at 17:07
  • @DeNovo: But being a pretty successful inventor, it is doubtful that Hall had the sort of intellectual disability associated with Williams. He simply looks like normal, young guy at 50.
    – releseabe
    Oct 15 '18 at 17:09
  • @releseabe yes, that's my point. "developing normally", specifically, had kids and didn't have an intellectual disability, rules out any disorder that comes to mind. Not to mention, "childlike facies" doesn't mean "looks like you're 20". Not really an answer, but i thought it could be helpful in a comment.
    – De Novo
    Oct 15 '18 at 17:11
  • @releseabe, is he known by his facial appearance or is it just your own observation? It's actually not that rare that people look 20 years younger, if you ask me. It can be a combination of normal genetics, hairstyle, facial expression, look (eyes), attitude to life...
    – Jan
    Oct 16 '18 at 16:21

I have not been able to find anything to back the hypothesis that there can be a development disorder which will slow body development, but retain mental development rates. However I have seen a slightly different disorder in journals.

  • Slow body development also with slow mental development
    This was reported by Andy Coghlan (2009) which covered the issue with 16 year-old Brooke Greenberg who had a physical development of approx. 5 years old.

    Scientists hope that by comparing the genome of a 16-year-old girl locked physically and mentally in a baby-sized body, that they may find the genes for holding onto youth

    (see also: Walker, et al. 2009 and Walker, et al. 2015).

    We previously reported the unusual case of a teenage girl stricken with multifocal developmental dysfunctions whose physical development was dramatically delayed resulting in her appearing to be a toddler or at best a preschooler, even unto the occasion of her death at the age of 20 years. Her life-long physician felt that the disorder was unique in the world and that future treatments for age-related diseases might emerge from its study (Walker, et al. 2015).

    Brooke died aged 20 from Bronchomalacia in her home town of Baltimore, MD. (The Telegraph, 2013)


Coghlan, A. (2009). Teen baby narrows search for “Dorian Gray” gene. New Scientist, 203(2715), 12-12 doi: 10.1016/S0262-4079(09)61749-8

The Telegraph (2013). Brooke Greenberg - obituary, The Telegraph [Online]
Retrieved from: https://www.telegraph.co.uk/news/obituaries/10428714/Brooke-Greenberg-obituary.html

Walker, R. F., Pakula, L. C., Sutcliffe, M. J., Kruk, P. A., Graakjaer, J., & Shay, J. W. (2009). A case study of “disorganized development” and its possible relevance to genetic determinants of aging. Mechanisms of ageing and development, 130(5), 350-356. doi: 10.1016/j.mad.2009.02.003 PMID: 19428454
FREE PDF: http://citeseerx.ist.psu.edu/viewdoc/download?doi=

Walker, R. F., Liu, J. S., Peters, B. A., Ritz, B. R., Wu, T., Ophoff, R. A., & Horvath, S. (2015). Epigenetic age analysis of children who seem to evade aging. Aging (Albany NY), 7(5), 334–339. doi: 10.18632/aging.100744 PMCID: PMC4468314
Full Accessible Text: https://www.aging-us.com/article/100744/text#fulltext
FREE PDF: https://s3-us-west-1.amazonaws.com/paperchase-aging/pdf/XHhjqD7fdWZMyww4C.pdf

  • This is something I remember reading about, in particular how the physician suggested that the condition might be significant to the study of ageing -- but this is probably not related to the situation of Hall.
    – releseabe
    Oct 16 '18 at 18:57

When looking at another person, or indeed even animals, there are features that tell our brains that they exhibit signs of "youth."

  • Larger, rounder head in proportion to rest of body
  • Larger eyes in proportion to rest of head
  • Smaller nose in proportion to rest of face
  • Smaller mouth in proportion to rest of face
  • Rounder, softer cheeks and other body areas ("baby fat")
  • Certain tooth crowding patterns
  • Smooth skin with few wrinkles

You can look at lists of these in guides for drawing younger faces, like this.

When these features are retained into adulthood, it is termed "neoteny."

Kallmann syndrome might fit what you're looking for, with pubertal delay, but it is not uniform in its manifestations. I cannot think of any other conditions that impart significantly youthful traits in individuals with otherwise average or above-average development. Maybe some of the connective tissue disorders, like Ehlers-Danlos, which gives skin extra velvety softness and translucence, but that's only one of many features of "youthfulness."

I suspect that some people simply have larger eyes, smoother skin, etc and appear younger. It is commonly said that certain races tend to have more individuals retain youthful features for longer, and there are some floating theories on increased collagen density or fat deposition location, but I've never seen any studies, and that's another topic altogether.

  • The "Hall" problem is probably as artificial as TinTin? (If his photo was taken when he was 18 then we just trample down a garden path). But would you count things like en.wikipedia.org/wiki/Kallmann_syndrome is fitting the more general description (that neotenic features dominate if just maturity is delayed…) Mar 30 '19 at 15:24
  • And I guess this plastique tells a very different story than the undated WP pic elyriact.smugmug.com/Journalism/General-news/Hall-statue/… (but the same page dates the photo to him being 39) lindahall.org/charles-martin-hall Mar 30 '19 at 15:27
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    @LangLangC You know, after reading more about it, Kallmann syndrome might fit the bill. It doesn't always manifest the same way, and sometimes there is some dysmorphism, but I actually wasn't aware that it wasn't associated with intellectual disability. Good catch! Edited.
    – DoctorWhom
    Mar 30 '19 at 17:50
  • Last year I also read about a case of mutism (anecdotal + popular newspaper) with flat affect. Allegedly 30 years of 'functioning' life (gestures, writing, highly intelligent), almost zero face muscle movement, almost atrophied, but in effect like extreme botoxing for decades. Very weird foto, somehow uncannily 'younger', but with a noticeable lack of subcuty fat. But I can't remember the language it was published in nor the native tongue of the 'case' (methinks Finnish). Mar 30 '19 at 18:21

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