Dermatology Online Journal

Correlation between IQ and dermatoglyphic indices of Down syndrome patients
Mostafa Saadat¹, Parvin Mehdipour ²
Dermatology Online Journal 12 (6): 25

1. Department of Biology, Shiraz University, Shiraz 71454, Iran. saadat@susc.ac.ir
2. Department of Human Genetics, Tehran University of Medical Sciences, Tehran, Iran

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Abstract

The fingerprint patterns, simian crease, and total ridge count of 41 mild and 61 severe mentally handicapped patients with Down syndrome (DS) were compared with a control group of 200 mentally normal individuals. Patients and controls were unrelated Iranian Muslims. Significant differences were observed within DS patients with different levels of mental retardation.

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Characteristic dermatoglyphic pattern of the palms, digits, and soles are well described in Down syndrome (DS). These studies from different populations showed good discrimination between DS and control groups. The digital and palmar dermatoglyphics features of DS include excess of ulnar loops, occasional radial loops on 4th and 5th digits, decreased total ridge count, and high incidence of simian creases on the palms [1, 2, 3]. The main purpose of the present report was directed to reveal the association between IQ and dermal configurations in the DS patients.

Material and methods

The IQ of patients was measured using Wechsler Pre-School and Primary Scale of Intelligence (WPPSI) [4]. Chromosomal studies were performed on all cases. The studied population was composed of 61 severe mentally handicapped (41 males, 20 females) and 41 mild mentally handicapped (16 males, 25 females) patients with DS. Prints were made by the inkless method from the patients and 200 mentally normal individuals (100 males, 100 females) as control group. Both groups were unrelated Iranian Muslims. Conventional methods were used in dermatoglyphic interpretation. The Chi-square test, Z-test and one-way analysis of variance were used. A p-value less than 0.05 was considered statistically significant.

Results and discussion

Patients and control groups were initially divided into two sex groups. Because no statistical differences were observed between sex groups for fingerprint patterns and simian crease (data not shown), the sex groups were pooled. The results of comparison between patients and control group showed that the dermatoglyphic findings (including finger patterns, simian crease and total ridge count) on DS in Iranian Muslims reveal the same results as those in the other populations [1, 2, 3] (see Table 1).

It should be mentioned that there are marked differences in each character between the two groups of our patients, showing the following trend in the severely handicapped patients:

• Increased ulnar loops and decreased whorl (χ2=13.10; df=3; p<0.01).
• High incidence of simian crease (χ2=9.24; df=1; p<0.01).
• Decreased total ridge count (F=21.37; df=5, 296; p<0.01).

There is no statistically significant difference between the two groups of patients for frequency of DS mosaic cases (3 and 4 mosaic cases in the mildly and severely affected patients, respectively; Z-value=0.55).

Results of the present study show that mildly handicapped patients in comparison with severely ones are more similar to mentally normal individuals in dermatoglyphic patterns. The present study is an effort to determine the usefulness of dermatoglyphic indexes in investigations and classification of DS patients into different mentally retarded groups.

Acknowledgments: The authors are grateful to the welfare organization and the centers of handicapped children for referring the Down syndrome cases and also for permitting blood sampling. This study was supported by Shiraz University.

References

1. Walker NF. The use of dermal configurations in the diagnoses of mongolism. J Pediatrics 1957; 50:19-29.

2. Bryant JI, Emanual I, Huang SW, Kornmal R, Lo J. Dermatoglyphics of Chinese children with Down's syndrome. J Med Genet 1970; 7:338-348.

3. Kamali MS. Topological formations of palmar dermatoglyphics in Down's syndrome. Int J Phys Anthrop Hum Genet 1985; 11:55-60.

4. Wechsler Pre-School and Primary Scale of Intelligence (WPPSI). Adaptation and standardization by A. Razavieh and S. Shahim. Shiraz University Press, 1995.

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