A study in the July issue of BMJ reviews research on a gene controlling the protein filaggrin. Defects in this gene are strongly associated with eczema, an allergic skin condition. Researchers noted that defects in this gene are related to allergic rhinitis (hay fever) and in the development of asthma in those with atopic eczema.

What is less clear — and what researchers noted as a subject for further study — is whether this gene is related to food allergies. It is believed that there is a genetic component to food allergies, as having a close relative with food allergies or another atopic condition is a strong risk factor. It’s also known that people with one allergic condition are predisposed to others later in life, a phenomenon known as the “atopic march.” Still to be determined is whether, and how, genes interact with environmental factors to cause allergies.

_{Rosanne A H M van den Oord and Aziz Sheikh, “Filaggrin Gene Defects and Risk of Developing Allergic Sensitisation and Allergic Disorders: Systematic Review and Meta-analysis.” BMJ. 2009;339:b2433.}

• Risk Factors for Food Allergies
• Eczema and Food Allergies
• What is the Hygiene Hypothesis?