Last summer, Sophie Hulme celebrated the tenth anniversary of her accessories brand by opening a flagship shop.
The boutique had all the signifiers of an independent label on the rise: a space on Marylebone's chichi Chiltern St, blond wood shelving, Instagrammable floors and, of course, tidy ranks of Hulme's bestselling Bolt, Swing and Pinch handbags.
Absent was any sign that within a year, the designer would decide to close the brand.
But three weeks ago, Hulme did just that, publishing an announcement via her Instagram feed.
"I am very sad to announce that these will be our last [collections]," she wrote.
"I have been battling with two very rare medical conditions. Over the years they have become increasingly problematic so, after some difficult deliberation, I have decided to close the company after 11 years in business."
For many, the announcement offered the first inkling that Hulme's life as founder of a thriving fashion business and a new mother (her son, Wilf, is 18 months old) was anything other than as glossy and aspirational as it looked.
Yet for most of her life, London born Hulme, 35, has suffered from an Ehlers-Danlos syndrome and Kleine-Levin Syndrome, two debilitating and misunderstood diseases.
"I haven't talked about my health much at all," she says, perched on the edge of a chair in her Islington townhouse.
"I'm very sensitive to the fact that there are other people who are suffering more, who may be wheelchair- or bed-bound, and the last thing I want to do is sound self-pitying. But if I can make somebody else realise what they have, or help other people understand a bit more about these illnesses, then it would be a massive missed opportunity not to do it."
The Ehlers-Danlos syndromes, or EDS, are a group of hereditary connective tissue disorders that can cause symptoms including joint hypermobility and pain, skin fragility, migraines and bleeding.
It's rare enough that, despite suffering with the symptoms since childhood, Hulme was only diagnosed in her mid-20s.
"It took me going round the houses until I eventually found a private specialist who could explain what was wrong," she says.
The mascot of the leading EDS charity is the zebra, echoing the medical maxim that when it comes to complex diagnoses, "when you hear hoofbeats, think zebras, not horses".
KLS, which Hulme was diagnosed with two years ago, is rarer still, striking only one or two people out of a million.
Nicknamed sleeping beauty syndrome, KLS causes bouts of excessive sleep, when the sufferer will be semi- or un-conscious for up to 22 hours a day, for days, weeks or months on end.
Hulme says she is "completely incapacitated" for about three days a week. "There have been times when my husband has had to wake me up to feed me, times when I'm completely unable to eat, drink or undertake any everyday activities without help."
Coping with both diseases - which are unrelated - is a matter of symptom management rather than a comprehensive therapy or cure.
Hulme sees a physio for joint issues, a gastroenterologist for digestive issues, a cardiologist for her heart, a migraine specialist for headaches, and so on.
Since flare-ups are unpredictable, the effect on her work has been dramatic.
"Awards, important meetings - fashion is one of those industries where you really need to show your face, and I hardly have."
She's cancelled work trips to Japan and China, one of her most important markets. EDS attacks often land her in A&E with "aggressive" gastrointestinal symptoms that medics typically interpret as overdoses.
Once, she took ill during a factory visit in Hungary and had to be rushed to hospital, with the factory owner accompanying her in the ambulance.
"I could do quite a good travel guide to the A&Es of the world," she jokes, totting up the score of emergency departments she's frequented, from LA ("the best - expensive though") to Kenya.
Yet when she isn't in the midst of an episode, "both conditions are kind of invisible. When you're okay, you look fine and nobody would guess."
Ironically, her illnesses are the main reasons she started the brand at all.
"I wasn't well enough to work full-time. I started my own business for the flexibility."
She set up her label as a Kingston University graduate in 2008, and "it was intended to be fairly low-key", Hulme says, but instead she found the kind of runaway success young designers dream of with the Albion, a minimal, boxy shopper with signature metal-plate hardware that heralded a move away from logo-ridden "it-bags".
The bags popped up on fashion show front rows and even made it to Downing St. (Samantha Cameron gave one to China's first lady, Peng Liyuan, as an exemplar of British design).
At its height, the company had NZ$17 million in annual turnover before rethinking the business model; today, Hulme says quarterly sales have doubled year-on-year.
Why close on an upswing? She and her team considered scaling back operations, or selling the brand, but all potential buyers stipulated Hulme's continued involvement. And Hulme has built a sustainable ethos into the brand - she was ambivalent about the prospect of seeing a new owner take it in a different direction.
"The design is looking the best it ever has. That was a real wrench. But at the same time, we can close it and feel really proud of it," she says. "That's a nice time to say, let's finish on a high.
"It's a massive relief to know that I can be gentle on myself for a bit, and stop fighting it."
Though little is known about the drivers of the two diseases, Hulme feels that stress exacerbates the symptoms.
"Certainly if I'm doing too much, it will make the next crash worse. That's part of taking this long period of time off, to try to tweak stuff and understand what can help, and try and come up with a bit of management."
The last two collections are limited-edition, with a numbered gold plate inside every handbag, and 10 per cent of the proceeds of each piece sold until the close of business will be directed to the Ehlers-Danlos Society and Kleine Levin Syndrome Support, charities that support people with Hulme's conditions.
"We felt that would raise awareness with every sale," she says.
She's looking forward to spending more time with Wilf - possibly the only toddler with a stack of personalised Globetrotter cases (from Hulme's collaboration with the luxury luggage-maker) beside his changing table - and she's sure she'll have a next act.
"I definitely want to do something creative again in the future. I don't think I'll be able to hold it in," she says. "But I'll do it in a way that fits into my life."