Prevalence of simian lines in general populations is usually 3-5%, but in medical populations the prevalence is typically much higher!
The simian line became famous for it's significance in Down's syndrome, but in time hundreds of academic scientifc publications have linked simian lines with a 'rainbow' of syndromes, diseases and other medical problems.
However, many medical problems have been linked with the single palmar crease! WrongDiagnosis presents a list of 123 causes that appear to be linked with the simian line.
Quite a few syndromes have been linked with the simian line. The table below presents percentages for the occurence of the simian line in relatively common syndromes (including patients & controls from various countries):
Quite some of the data above is summarized in:
- Hautleistenfibel, A. Rodewald (1981)
- Dermatoglyphics in Medical Disorders, Schaumann & Alter (1976)
Other more rare syndromes that are linked with the simian line are e.g.:
• Aarskog-Scott syndrome;
• cri-du-chat syndrome (cat-cry) [5p-] - 82.2 %;
• Cohen syndrome;
• Cornelia de Lange syndrome - 65.2 %;
• fetal alcohol syndrome;
• Kabuki syndrome - 18 %;
• Noonan syndrome;
• Patau syndrome [trisomy 13] - 59.5 %;
• Poland syndrome;
• Rubella syndrome;
• Rubinstein-Taybi syndrome - 39.0 %;
• Seckel syndrome;
• Smith-Lemli-Opitz syndrome - 78.4 %;
• Warkany syndrome [trisomy 8] - 37.5 %, 47.1 %;
• Williams-Beuren syndrome;
• Wolf-Hirschhorn syndrome - 52.3 %;
• Zellweger syndrome;
• 18p-, 18q- and 18r syndrome - 14.3 %, 44.8 %, 13.0 %.
Beyond these syndromes (which are usally caused by- or featured with genetic aberations), the simian line has also been related to various (non-)genetic diseases such as: diabetes mellitus (type 1 & 2), familial deafness, leprosy, and rheumatoid arthritis.
Also, the simian is more common in psychiatric populations such as seen in: schizophrenia (psychotic disorders) & ADHD.
But this doesn't implicate that the simian line can be associated with any diseases. For example, auto-immune diseases (which typically have a higher occurence in females than in males) are generally not associated with a higher occurence of the simian line (which is more common in males). Though the hand in diabetes mellitus type 1 could be the exception that confirms the rule!
• Psychology & behavior: the simian line!