Your Questions Answered: Is Raynaud’s syndrome hereditary and more

Date: Mon 10th February 2020

Despite Raynaud's syndrome being a relatively common condition, with up to 10 million people in the UK diagnosed, several questions remain about the nature of the disease and the reasons behind why some people are predisposed to suffer from it, as well as why it can be so debilitating in one person and very manageable in another. Raynaud's can have a hugely limiting impact on people's lives, with some individuals no longer able to work or partake in hobbies. Further research into this area may be profoundly beneficial to our community, as it may facilitate the development of new treatment interventions that will lead to improvements in quality of life.

Is Raynaud's hereditary and if so, what is the inheritance pattern?

It is thought that Raynaud's can sometimes run in families, with some studies suggesting that approximately 30% of people with a first-degree relative (parent, sibling or child) who has primary Raynaud's also have the condition. However, there has not been a sufficient number of investigations into this to successfully define an inheritance pattern. Furthermore, as uncertainty remains about which variations in which genes may be causal factors of Raynaud's, this presents a further challenge for researchers in determining the inheritance pattern, since genes cannot be looked at in isolation to see if they are passed down to relatives. Research could therefore be focussed on distinguishing specific gene variations and assessing which of these variants have been passed on in families where two or more members have Raynaud's, to thus calculate inheritance patterns.

What is the root cause of someone developing Raynaud's Phenomenon?

A major question that our community often wants to know the answer to is: “what caused me to develop Raynaud's". This is separate from the occurrence of Raynaud's attacks when exposed to low temperatures or to sudden stress, but requires focusing on why this group of individuals are so susceptible to these environmental or emotional triggers. Essentially, we need to know what makes their body exhibit the physiological response of narrowing their blood vessels when these triggers occur.

There is some evidence to show that variations in genes involved in the process of the small blood vessels responding to cold or stress may contribute to an individual's risk of developing Raynaud's syndrome, however there is still a lack of clarity concerning how these gene variations are linked to this abnormal blood vessel response. For example, research conducted in 2018 at King's College London implicated a variant within the NOS1 gene as significantly associated with Raynaud's in the general population, nevertheless more work needs to be performed assessing the mechanisms that lead to the presentation of Raynaud's.

Why are more women diagnosed with it than men?

It is widely acknowledged that women are more likely to be affected by Raynaud's than men, as reflected by the stark contrast between the diagnosis rates of the two genders, which is currently at one reported case in men for every four cases in women. Whilst this is well established, there is weaker understanding of why exactly this is the case.

A recent study conducted by researchers at the University of Shizuoka in Japan, entitled ' G-protein coupled oestrogen receptor-mediated non-genomic facilitatory effect of oestrogen on cooling-induced reduction of skin blood flow in mice', examined the relationship between blood-flow and hormones in mice. From the results, the team proposed that the hormone oestrogen may in part be responsible for the development of Raynaud's, as the mice treated with the highest concentration of this hormone experienced the greatest reduction in blood flow because of increased sensitivity to cold temperatures in their extremities.

Oestrogen is a naturally occurring hormone that is generally produced at higher levels in women than in men. Oestrogen levels are increased at the onset of puberty and facilitate the development of secondary sex characteristics specific to females, and the hormone has a central role in the regulation of the menstrual cycle.

Despite research such as this implying the potential role of oestrogen in the development of Raynaud's in young women, it is important to note that there is a lack of studies investigating the causal effect of oestrogen on Raynaud's. Much more work therefore needs to be invested into evaluating whether it is solely a higher concentration of oestrogen in female bodies increasing the rates of Raynaud's diagnosis in women compared to men.

These are just a few examples where there are gaps in knowledge concerning Raynaud's. Conducting research into these areas would be of direct patient benefit and contribute to one of the four streams of research in our strategy, which focuses on causes, quality of life, precision medicine and early detection.

If you are interested in helping SRUK to fund work that will help to improve the quality of life of our community, then please donate today. We rely on the generosity of the community to continue to support groundbreaking research in both scleroderma and Raynaud's.

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If you'd like to learn more about Raynaud's, then head to our recent article: Latest research into Raynaud's syndrome.