Fingerprint matching may predict health risks

The classification of fingerprint patterns is relatively complex, and is generally divided into three categories, each of which can be divided into two subtypes. (Image provided by the author)

"Which genes make us humans unique?" The editorial board of Science magazine published 125 most challenging scientific questions in 2005 and 2021 respectively, and mentioned this question in both publications. From this, it can be seen that humans have never stopped exploring themselves.

Among the exposed skin of humans, the palm skin of the hands and feet is different from the skin of other parts of the body. The palm skin of the hands and feet has no sweat hair and the epidermis is thicker. This is a special skin of humans and other primates. However, this layer of skin is distributed with patterns composed of concave and convex ridges. Human ridge patterns, especially fingerprint patterns, are more complex and diverse. From a genetic point of view, "what kind of genetic variation makes humans present such unique and diverse fingerprint patterns?"

Early studies have found that the types of fingerprint patterns, such as arch, dustpan, and bucket, and the total number of ridges, are up to 60%-90% affected by genetic factors, and there are major genes. Driven by the Human Genome Project and the Functional Genome Project, researchers have located several loci associated with fingerprint patterns of European ancestry groups through whole genome association analysis. However, these loci have not been reported to be involved in human development, and there is little in-depth understanding of the underlying biological mechanisms.

In recent years, by optimizing the tools for acquiring and storing dermatoglyphics and refining the phenotypic quantification methods, our research team has accumulated fingerprint patterns of more than 20,000 people, identified 43 genetic loci associated with fingerprint patterns, and found that the genes affecting fingerprint patterns of different fingers are not the same. These variant sites may show certain differences in different ancestral groups in Eurasia due to the size or frequency of different allele effects. The research team found that these genes are significantly enriched in pathways related to limb development and formation. There is a significant correlation between the fingerprint patterns of the three middle fingers of both hands. They may be mainly affected by neighboring genes in the same genetic factor region, which explains the "fingerprint module phenomenon" discovered in the 20th century from a genetic perspective.

During human development, the genes were dynamically expressed in time and space, and were concentrated in mesenchymal cells, which are related to limb development, rather than epithelial cells. This study supports the role of the genes in shaping limbs and fingers, rather than directly affecting skin development function.

So, is there really a relationship between fingerprint patterns and hand characteristics? The research team found that fingerprint patterns are widely correlated with limb phenotypes such as finger length: the longer the little finger is, the shorter the palm length is, and the more bucket-shaped patterns there are on both hands; and the shorter the distal knuckles where the fingerprints of the index fingers are formed are, the more bucket-shaped patterns there are.

The contribution of this study is that it explains the significant relationship between dermatoglyphic ridges and skeletal development, because they have a common genetic basis, reflecting the typical "one cause, multiple effects" in biology. This also provides an important theoretical basis for the study of the association between dermatoglyphics and other human phenotypes and development-related congenital genetic diseases.

Through statistical analysis of skin texture features and congenital genetic diseases, the research team screened out the best combination of skin texture features for patients, which is expected to be used in early screening of congenital diseases in newborns, to predict health risks in advance, detect early, and take intervention measures. This is also in line with the research goals of the "International Human Phenotype Project" led by Fudan University, to build a strong correlation "navigation map" between phenotypes, to find early prediction indicators for specific diseases, to analyze the mechanism of disease occurrence from multiple angles, and to provide new directions for future life and health research.

(The first author Li Jinxi is a young researcher at Fudan University, the second author Jin Li is an academician of the Chinese Academy of Sciences and a professor at Fudan University, the third author Zhang Haiguo is an associate professor at Shanghai Jiao Tong University, and the fourth author Wang Sijia is a researcher at the Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences)