SINGAPORE – Thirteen-year-old Kayden Soh must follow a strict diet – no fruit, no milk, and no candy – because his liver cannot process sugar. He also drinks plenty of cornstarch water.

He mixes about a teaspoon of uncooked cornstarch with water and drinks the concoction every few hours, even in the middle of the night.

Without it, he could have dangerously low blood sugar, which is life-threatening.

Kayden suffers from Glycogen Storage Disorder Type 1A (GSD1A), a rare condition that affects the way his body breaks down food into glucose, or energy for the body, due to a missing liver enzyme. It affects about one in 100,000 people worldwide.

Uncooked cornstarch is a complex carbohydrate that the body digests slowly. When consumed, the cornstarch releases glucose slowly into the bloodstream over several hours.

This slow release acts as a continuous, external source of glucose, mimicking the function of the missing liver enzyme and helping to manage blood sugar levels between meals and during fasting, especially overnight.

“Kayden first showed symptoms when he was nine months old. His belly was bloated. We took him first to the polyclinic and the doctor told us that it was quite common for babies to have a bloated tummy and asked us to just apply ointment. That was what we did,” said his mother, Ms Yong Xiao Ping, a 35-year-old interior designer.

However, her maternal instinct told her the problem could be more serious.

“His tummy continued to bloat so that is when I decided to just take him to Mt Alvernia (Hospital) to consult the paediatrician there. The doctor wrote a referral letter and asked us to take him to KKH,” she told The Straits Times.

After some blood tests and a biopsy at KK Women’s and Children’s Hospital (KKH), Kaden was diagnosed with GSD1A.

The condition is caused by a deficiency in an enzyme called glucose-6-phosphatase (G6Pase), which is mainly found in the live...