Comprising less than 0.001% of the cases of ichthyosis, Harlequin-type ichthyosis was uniformly fatal in the past. It is an autosomal recessive condition, with both parents having to carry the same mutation of the gene ABCA12. Historically, it was known to be a disease found in first-degree and second-degree consanguineous unions (children from siblings or first cousins), but today it is not one of the major inbreeding-related or Founder effect syndromes.
Harlequin infants are born with thick, plate-like keratin “armor”, often accompanied by ectropion (out-turned eyelids - that’s what causes the blood-like eye appearance). Historically, they would generally die before 14 days of age, due to dehydration, overwhelming infection/sepsis, breathing problems (from the keratin plates restricting inhalation), or related problems. None were known to survive beyond 5 months. These days, some people who are affected by Harlequin-type ichthyosis manage to survive infancy, though the percentage is still barely above half.
The high retention rate and cracking of the plates of keratinous cells leaves the dermis vulnerable to disease and dehydration, but frequent application of Isoretinoin can allow the skin to shed keratin layers faster than it produces them. This allows for a higher level of flexibility and protection (because of no deep fissures in the skin). Currently, there are multiple people who have Harlequin-type ichthyosis treated by Isoretinioin and therapeutic baths who have survived long beyond anything ever seen in the past. Despite the inconvenience their condition poses, some of them present a pretty darn inspirational way of living:
Nusrit “Nelly” Shaheen is 28 (born in 1984) and studied at Hereward College in the UK. She lives a very active lifestyle, and is the oldest living survivor of Harelequin-type ichthyosis.
Ryan Gonzalez is 25, and lives in the United States, where he participates in triathlons and swimming competitions. He uses a different regimen from Nelly in his treatment, where he relies almost exclusively on Isoretinoin ointment. Both require a huge caloric intake to match their skins turnover rate, though.
Today, there are 56 other known survivors of Harlequin-type ichthyosis that are beyond 2 years of age. It may seem like a tiny number, but a 53% survival rate at 2-years-old is certainly better than zero percent! Hopefully the future will hold new therapies for all of the ichthyosis syndromes.
Harlequin Fetus from 1880 at Museum Vrolik, in Amsterdam, Holland. Photograph by Zzzak.