The Siberian cat is recognized for having lower levels of the major cat allergen Fel d 1 compared to most other breeds. According to research: • About 50% of Siberian cats have Fel d 1 levels lower than those of normal cats, and roughly 15% produce very low levels of the allergen, making them suitable for homes with severe cat allergy sufferers. However, Fel d 1 levels can vary significantly among individuals within the breed, even in litters from low-allergen parents. • Fel d 1 is a glycoprotein produced primarily in the lacrimal, salivary, sebaceous, and perianal glands. The allergen is spread mainly via saliva during grooming and skin glands onto fur, which can become airborne and cause allergic reactions. • Neutering significantly reduces Fel d 1 levels, as it’s hormonally regulated. Both male and female Siberians can produce low levels, but unneutered males typically produce the highest amounts. • Genetic studies have identified mutations in the Ch1 and Ch2 genes that encode Fel d 1 in Siberian cats. These mutations could influence the allergenic properties and protein expression, providing potential markers for breeding hypoallergenic cats. • Studies measuring Fel d 1 concentration in Siberian cat saliva have found levels ranging generally below 1.5 µg/mL in some individuals, while others show elevated levels. It’s the first breed where genetic structure of Fel d 1 genes was investigated to explain reduced allergenicity.In summary, Siberian cats tend to have significantly lower Fel d 1 production than other breeds due to genetic and hormonal factors, which supports their classification as hypoallergenic cats, although individual variation still exists. This makes them a preferred choice for cat allergy sufferers, but allergy testing and monitoring are still recommended for sensitive individuals.References included detailed genetic, biochemical, and breeding studies contributing to our understanding of Fel d 1 expression in Siberian cats and their hypoallergenic potential有關西伯利亞貓Fel d 1過敏原的量化研究，主要發現如下： • 研究顯示西伯利亞森林貓的Fel d 1產量普遍低於其他貓種，約為其他品種的五分之一，有50%的西伯利亞貓Fel d 1水平明顯較低，其中約15%非常低，適合過敏嚴重者飼養。 • Reddit討論指出，母西伯利亞貓每克產生大約200微克Fel d 1，而一般貓每克可達63,000微克。去勢公貓與母貓的Fel d 1產量相對較低，未去勢公貓產量較高。 • 科學論文中採用唾液樣本測量Fel d 1，數值波動較大，但低Fel d 1生產貓的數值較穩定。這些研究指出性別、體重及毛色對Fel d 1數值影響不大，年齡則呈負相關，年長貓Fel d 1量較低。 • 另一項遺傳學研究發現西伯利亞貓的Ch1和Ch2基因（Fel d 1編碼基因）存在多種突變，可能影響蛋白過敏性，為低致敏基因的選擇提供了依據。總結來說，西伯利亞森林貓Fel d 1的量化研究支持其為低過敏貓種，且Fel d 1含量與品種特徵及基因有關，但個體間仍有變異，過敏體質者需個別測試確認合適性.西伯利亞貓的Fel d 1過敏原量化研究顯示，約有50%的西伯利亞貓Fel d 1水平較一般貓低，其中約15%非常低，適合過敏體質較嚴重者。母貓每克產生約200微克Fel d 1，相較一般貓每克63,000微克明顯較低。Fel d 1唾液濃度在不同時間及個體間有波動，但低產生者較穩定。研究還發現西伯利亞貓Ch1和Ch2基因有多種突變，可能影響Fel d 1過敏性。性別、體重與毛色對Fel d 1影響有限，年齡呈負相關，年長貓Fel d 1較低，支持西伯利亞貓為低過敏貓種，但仍需個別測試.