Severe life threatening asthma occurs in U.S. children of Puerto Rican descent at an alarming rate and a genetic variant may be responsible for this problem. Scientists and physicians have teamed up to find out if the ß₂AR gene variant, in combination with certain environmental factors, might be responsible for this problem. Early identification of this gene variant has the potential to decrease the level of asthma severity experienced by these children and prevent its related childhood deaths. Additionally, this could also reduce the asthma health care costs in the U.S., which are currently estimated to be $18.5 billion dollars (Tan et al. 2009).

Scientists and physicians in the U.S. have teamed up as part of the Genetics of Asthma in Latino Americans (GALA) study to examine how genetic variants may combine with environmental factors to increase Puerto Rican children’s risk for asthma onset and severity.

For example, studies to date have found that Puerto Rican children in the United States are at an increased risk for severe, life-threatening asthma when compared to other children, including other Latino children and white children (Lara et al. 2006).

Specifically, in comparison to other Latin American children, Puerto Rican children have:

1. the highest mortality rate from asthma,
2. the highest incidence of asthma compared to other Hispanic children,
3. a lower response rate to bronco dilators, and
4. different reaction to the most commonly prescribed drug for asthma worldwide, albuteryl (Burchard et al. 2004, Choudhry et al. 2005).

This increased asthma risk may be due to genetic variants in these children. It is possible that early identification of these gene variants and implementation of strategies to monitor the disease in this population could reduce the cost associated with asthma in the U.S., which is currently estimated at $18.3 billion dollars (Tan et al., 2009).

For example, one study found that genetic variants at the beta2-adrenergic receptor (ß₂AR) modified the severity of an asthmatic attack in U. S. individuals of Puerto Rican ethnicity (Choudhry et al. 2005).

The ßeta 2 adrenoreceptor protein extends across airway smooth muscle cells, enabling airway smooth muscle relaxation. The ß₂AR gene variant, in combination with certain environmental factors such as exposure to dust mites, can cause irregularities in the level or function of this protein.

Specifically, the airway muscle may not relax when it should, in some cases, thereby causing the airway to constrict. Irregular airway receptor protein expression can also reduce normal lung function, which is known to occur in patients who have asthma.

In a surprising finding, scientists in Australia found that it may be possible to identify the ß₂AR gene variant in infants as early as one month of age (Turner et al. 2004). The Australian scientists also followed these children by conducting an 11-year longitudinal study, from age 1 month to 11 years old, where they regularly measured the children’s airway responsiveness. The scientists found that the early airway hyper-responsiveness that was identified at one month of age in infants with the ß₂AR gene variant was also linked to reduced lung function and asthma severity in later childhood (ibid).

Based on these results, it may be possible to screen U.S. infants of Puerto Rican descent to identify the ß₂AR gene variant. If the ß₂AR gene variant is found, like in Australia, it could provide an opportunity to design programs to monitor and better manage the infants’ future risk for developing asthma. This would have the potential to reduce asthma severity and mortality in these children and also reduce the related health care costs.

One way a monitoring strategy could accomplish this is by the design and implementation of written asthma management plans.

In one case-control study on children ages 0 to 14 years, scientists found that patients with written asthma management plans were half as likely to have a hospitalization or an emergency department visit as those who lacked a written plan (Teach et al. 2006).

This could make a difference in the U.S. where emergency departments, which are commonly used for the acute and chronic management needs of patients with asthma, account for nearly 2 million asthma-related visits each year (Shatz, Rachelefsky and Krishnan 2009).

In fact, this problem is so striking that a specific objective of the U.S. Healthy People 2010 program is a nearly 50% reduction in the rate of emergency department visits for asthma in children younger than 5 years (Teach et al. 2006).

The early identification of ß₂AR gene variants in Puerto Rican children could also serve to better inform physicians regarding drug treatment decisions. For example, data shows that the ß₂AR gene variant affects the responsiveness of the drug “albuteryl,” which is the most commonly prescribed treatment for asthma worldwide (Choudhry et al. 2005).

Importantly, albuteryl, which is often administered as an inhaler or nebulizer, is less effective for Puerto Rican children who have the ß₂AR gene variant (ibid).

Information about a child’s ß₂AR gene variant may also be important for parents to provide to a child’s classroom teacher.

It is clear that there are many potential advantages to be gained by the early identification of the ß₂AR gene variant in Puerto Rican children.

These include reducing asthma disease severity and mortality, as well as reducing the health care costs associated with these events.

And these potential gains may increase in size in the future. Today Puerto Rican individuals represent 11% of the 42.6 million Latinos in the United States (excluding residents of Puerto Rico), and that figure is growing (Choudhry et al. 2005). Latinos are the largest, youngest, and fastest growing minority population in the United States, accounting for 14% of the nation’s total population (ibid). By 2050, it is predicted that 25% of the U.S. population will be Latino (ibid).

The Genetics of Asthma in Latino Americans (GALA) study is an ongoing multicenter international collaborative effort designed to identify and directly compare clinical and genetic risk factors associated with asthma and asthma severity among Puerto Ricans and Mexicans.

If you would like to find out more about this study, or you are interested in participating in the GALA study, please let us know. Write to dnascribestory@optimum.net.