Fluctuating asymmetry in dermatoglyphics of non-insulin-dependent diabetes mellitus in Bangalore-based population

Background: The aetiology of NIDDM is believed to be as a consequence of genetic and environmental factors that impair metabolism. While little can be done on the genetic component, much can be done as a preventive measure in NIDDM. Because nothing much can be done prenatally, researchers have resorted to studying physical variables like dermatoglyphics (DGs). Dermatoglyphic patterns form on the finger pad and the palm prenatally and remain unchanged throughout life, thus these features may serve as markers for fetal origin of adult disease like NIDDM. Thus the concept of fluctuating asymmetry (FA) which has been defined as random differences between the right (R) and left (L) sides of a morphological trait has gained prominence in diseases like schizophrenia. When the distribution of R-L differences in a population sample approximates a normal curve with a mean approximately equal to zero, the variance of distributions of R-L difference is a measure of FA. Studies have shown that genetic factors may also have a link to FA in finger and a-b ridge counts. No studies have been reported on FA in NIDDM. FA derived from quantitative parameters in DGs of NIDDM may throw light on fetal origins of an adult disease. Hence this study has been undertaken.
Aim: The present study aims at deriving FA from quantitative parameters in DGs of NIDDM compared to controls in the Bangalore based population.
Materials and Methods: Bilateral rolled finger and palm prints of 150 NIDDM patients (Males - 75, Females - 75) were compared to 120 controls (Males - 60, females -60) from Bangalore based population. FA measures derived from quantitative parameters (finger ridge counts, a-b ridge counts, main line index and palmar angles) were analysed.
Results: Comparisons were made in all parameters between homologous fingers of both hands using Pearson′s product moment correlation coefficients (r). The difference in correlation coefficients between cases and controls was calculated using Fisher′s Z transformation. 1-r2 an estimate of error variance thus measures FA. FA measures were significantly higher in NIDDM males for the 5th finger (FA=2.04) and for the palmar angle ′dat′ (FA=2.24); for the NIDDM female a high FA was found in the 2nd finger (FA=2.17) compared to controls.
CONCLUSION: Overall measures of the above ridge counts and angles and their derived measures of FA were prominent features of NIDDM in this sample.