Not only do I have mcs but I have a sister who has it too.

Does anyone know of any studies that suggest mcs is genetically related?

One arguement that I can think of to support the idea is given the number of people that are exposed to toxins of all kinds on a daily basis , it's a wonder that there are not more people who are suffering from mcs , at least according to the statistics.

Scientists are finding out all the time that rare genes are responsible for different ailments and disorders.

These illnesses do seem to run in families. Myself and my mum both developed chronic fatigue syndrome (ME/CFS) in 1990 and my younger sister became ill as well around 1998.

Research is still limited (don't we know it!) but small genetic variations known as single nucleotide polymorphisms (SNPs) that affect the function of specific genes and the proteins (e.g. enzymes) they code for seem to make some people more susceptible to MCS, ME/CFS and other environmental illnesses. Relatively common SNPs in certain genes can lead to poor functioning of enzymes involved in detoxification...and these have been found to be more common in people with MCS.

See this study that found SNPs in genes that reduced glutathione production and acetylation (both vital for detoxification) were more common in MCS patients than healthy controls:

A cross-sectional study of self-reported chemical-related sensitivity is associated with gene variants of drug-metabolizing enzymes

The good news is that testing for common SNPs (including those in this study) is now widely available from commercial labs and results can help reduce the "shooting blind" element of treatment!

well I have MCS , my daughter has sensitivity to Caffeine with very similar symptoms but clearly more controllable, and my brother has Aspergers which is also linked to the environment, so I'd say so.