Millie’s Story: CSID

Millie's story-CSID

For the first three years of Millie’s life, she was very unwell. Misdiagnosed six times and dismissed by doctors on numerous occasions, her parents were at a loss until they discovered Millie had Congenital Sucrase-Isomaltase deficiency (CSID), as her Mum explains.

“Since birth, Millie has been very unwell. As a baby, she would scream in agony for hours on end. We took her to A&E a few times, not knowing how to relieve her pain.

“That’s what babies do. They cry,” said one consultant, who sent us home.

We knew something most definitely wasn’t right.

She was always vomiting, profusely. And diarrohoea and vomit caused her little bottom to be covered in sore red open blisters and welts.

As she got older, she struggled to eat anything, and she didn’t do much toddling. All she could manage was to lie on the sofa, exhausted, clinging, sobbing and grumpy. Her tummy was always terribly bloated. Her first word was ‘ow’.

She spent a year eating five foods, which helped her symptoms somewhat subside.

We couldn’t give her any medicine, as Calpol and Nurofen produced torrents of vomit. The only way to ease her pain was to gently rub her tummy and rock her gently for hours. When she could string a few words together, it was, “Mummy, I’m tired”, from the moment she woke up.

We went through numerous diagnoses but none of them resonated.

When she vomited profusely after a tiny sucrose pill of some homeopathic treatment, we looked into sucrose intolerance.

We fought and fought for another gastroscopy, because we knew she was poorly. We wasted a whole year waiting for another gastroscopy and watched our daughter’s health deteriorate – a whole year of unnecessary pain, stress and suffering.

In desperation, I put her on a Keto diet and removed sugar and starch from her diet. The change in this little girl was extraordinary. For the first time, she started to blossom.

Then after a ten-day trial of Invertase, which we fought for, and paid for, we saw a little girl with energy and a vigour for life, which we had not seen before. But once our Invertase supplies ran out, we were back to square one

After three and a half long years of discomfort, pain, fatigue, hospital visits, blood tests, six misdiagnoses, two gastroscopies, being prodded and probed by seven different consultants, three dieticians and two nutritionists in four different hospitals, she was diagnosed with Sucrase-Isomaltase Deficiency and anaemia.

We are hopeful life can now properly start for Millie, and that we can start to enjoy our little girl and rebuild her confidence.

 We are relieved we have finally reached a diagnosis; sad that the system has let us down; exhausted that we have had to battle so hard to get to where we are today; and grieving for the normal life we know she can’t have.

We hope others will learn from this painful and stressful journey and understand that parents need to be listened to. There is nothing stronger than a mum’s gut instinct. If our story saves, even just one family, from having to endure what we have done, it will have been worth it.”

If you or someone you know has been diagnosed or is living with CSID and would like some support with your diagnosis, please get in touch with our Core Services team to see how we can support you. You can reach our Core Services team on 0845 241 2173 or

Want to share your story? Please email Toni (our Communities Engagement Officer) via:

Skip to content