C Oyinbo, H Fawehinmi
anomalous palmar crease, epidermal lines, prevalence
C Oyinbo, H Fawehinmi. Prevalence of simian and Sydney creases in the Ijaws of South- South Nigeria. The Internet Journal of Biological Anthropology. 2008 Volume 3 Number 2.
Simian, and Sydney creases are anomalous palmar crease that had generated medical attention as their presence correlate strongly with several human chromosomal abnormalities and diseases. Works on these creases have been done on several human populations; racial and ethnic, but no specific documented study had singled out the Ijaws of South- South Nigeria in respect to these palmar creases aberration. This study was to determine the prevalence of simian and Sydney creases in apparently normal individual of the Ijaw ethnicity of South- South Nigeria and to compare it with known population prevalence. Five hundred and seven subjects of Ijaw origin were randomly selected. Subjects palms were physically inspected for simian and / or Sydney crease. Observations were categorised into gender and right / left palm(s). Relationship between creases, gender and right or left palm was assessed by Fisher's exact test. Results shows that the prevalence of male with simian crease in the male population and in the entire population was 3.98% and 1.77% respectively, while that for female were 4.27% and 2.37%. Sexual predilection was not statistically significant (p > 0.05). Subject in the study population with simian crease is 4.14%. Sydney crease was uncommon, it occurred in 0.19% of individuals. Values in the Ijaws of South- South Nigeria were generally lower than those of the Orient and higher than those of the Caucasians. Confirming that physical anthropology trait varies amongst populations.
The scientific study of dermal ridges of the hands and feet was first begun in 1823 by Evangelista Purkinje 1 . Overtime, several studies have emerged which progressively show that dermal ridges of the hands and feet can be employed in the prediction of a range of medical conditions and diseases 1,2, 3, Palmar crease are epidermal lines that produce typical or atypical patterns on the palmar surface of the hand. Simian, and Sydney creases are anomalous palmar crease that had engender medical attention, because it is known that their presences correlate very strongly with several human chromosomal abnormalities and diseases 4, 5 . Palmar crease aberrations are most times indicative of chromosomal aberration and other intrauterine assault occurring early in pregnancy 3 . Dermal ridge configurations begin to develop about the 12th week of gestation. Dermatoglyphics polymorphism results from the interplay of genetic and environmental factors during the early stages of ontogenesis 3 . Epidermal lines or dermatoglyphics analysis is now a valuable companion to other methods used for diagnosis of some genetic diseases such as phenyloketonuria and syndromes genetically determined (e.g., Down, Turner or Klinefelter syndromes) 6 . Consequently, they are employed as predictive indices in apparently normal infants in whom cryptic damage may manifest later 7 . It has enabled early detection of genetic abnormalities such as Down’s syndrome and many other defects that occur
Material and Methods
This cross-sectional study was conducted in Niger Delta University, Wilberforce Island, Bayelsa state, Nigeria. Five hundred and seven subjects of Ijaw origin, (n = 507), comprising of 281 female and 226 males were randomly selected from the student population. Subjects whose father and mother were not of Ijaw ethnic origin were excluded from this study. Also excluded were individuals with limb anomaly, or any morphological anomaly /syndrome. This study did not discriminate between the variants of either simian
This work shows that the prevalence of simian and Sydney creases in normal individual of the Ijaw ethnicity of South- South Nigeria is 4.1% and 0.19% respectively (Table 1).
Simian crease: The percentages of male with a simian crease in at least a palm in the studied male population and in the entire studied population were 3.98% and 1.77% respectively. The percentages of female with a simian crease in at least a palm in the studied female population and in the entire studied population were 4.27% and 2.37% respectively. Sexual and hand preponderance were not statistically significant (
Sydney crease: No female subject was observed with a Sydney crease in either of the palms. A Sydney line was observed in the right palm of a male subject. The percentage of subjects in the study population with a Sydney crease is 0.19%.
* Significant (Fisher's exact test p < 0.05 in all case)
We have demonstrated that the prevalence of simian crease was 1.8% in male and 2.4% in female of the Ijaws of South-South Nigeria. The general population prevalence was 4.1%. Gender or hand predominance was not experiential (p > 0.05). This agrees with the work of Kamali 8 , but in variant with the study of Hernandez 18 in respect to sex preponderance. The population prevalence of simian crease in the Ijaws is significantly different (p < 0.05) from those of the Caucasian except for the Germans, the Orients except for the Eastern Japanese, the Gypsies and African Pygmies 19 (Table 2). We also observed that the general pattern was an increase in prevalence rate as we move from the Caucasian to the Orients (figure 2). This discrepancy can be explained by ethno-historic and geographic variations between different human populations 21, 22 . Dar
We are grateful for the assistance of Miss Arijovwode Emuobosa Precious and Mr Iyevhobu Lamai Kenneth for their help in data collections.