Genetic disease patterns in Japan: a review

Area of Science:

• Human biology
• Population genetics
• Medical genetics

Background:

• Ecological and social factors influence population genetic structure.
• Understanding genetic disease incidence and consanguinity is crucial for human biology.
• Japan presents a unique case study for genetic disease frequencies and inbreeding patterns.

Purpose of the Study:

• To analyze the incidence of genetic diseases in Japan compared to other populations.
• To review consanguinity studies in Japan and assess inbreeding levels.
• To project worldwide trends in inbreeding and their impact on genetic disease frequencies.

Main Methods:

• Comparative analysis of genetic disease incidence across populations.
• Review of historical consanguinity data from Japanese villages.
• Examination of social and ecological factors influencing mating patterns.

Main Results:

• Certain genetic disorders are less frequent in Japan, while others occur at higher rates (approx. 1 in 100 newborns).
• Consanguinity rates in early 20th-century Japanese villages were high (8.6%–58.0%), though declining nationally.
• Inbreeding remains significant in some Japanese villages due to traditional social values.

Conclusions:

• Japan exhibits distinct genetic disease profiles influenced by population structure and consanguinity.
• Socially prescribed mating patterns globally may sustain or increase the frequency of certain genetic diseases.
• Continued research into the interplay of ecology, social factors, and genetics is vital for understanding human population health.