Asthma

Intro

• common inflammatory disease caused by genetic and environmental factors
• Airway narrowing and excess mucus cause breathing difficulties
• symptoms: wheezing, chest tighness, shortness of breath and coughing
• mild to severe and symptoms can come and go
• can results in Asthma attacks
• Affects all ages but usually starts in childhood
• most common chronic disease in children

Causes

• exact cause unknown
• results of strong response of the immune system to an allergen in the environment e.g ragweed allergen - some people may not react and some may react strongly - genetic explanation?
• environmental factors may affect risk of asthma such as airborne allergens and virus infections in infancy when the immune system is still developing

Environmental Factors

• Exposure to cigarette smoke during pregnancy or during a child's first few years - affect lung growth and development
• Exposure to different microbes in the environment - affect development of the immune system - can either increase or protect against risk of developing Asthma
• Workplace exposures - chemical irritants, industrial dusts = occupational asthma
• Poor air quality from pollution or allergens may worsen asthma - gases from heaters or vehicles, pollen, dust etc.

Other Medical Conditions

• Allergies 
• Obesity
• Respiratory infections and wheezing

Race

• African Americans and Puerto Ricans are at higher risk of asthma that other races

Gender

• In children more boys that girls, in adults more women than men

https://www.nhlbi.nih.gov/health-topics/asthma

Genetic Contribution

• predicted by clustering of asthma and allery symtoms among relatives and twin studies - ranges from 55-90% genetic contribution

https://www.ncbi.nlm.nih.gov/pubmed/30805318 - genome predictors and phenotypes

Candidate Gene Analysis

• 2017 study BA Almomani et al
• 10 candidate genes e.g STIP1, ALOX5, ABCC1 - assessing association with Asthma in a Jordanian population of Arab descent
• Case control studdy - 245…