Ashley Zambelli, a 26-year-old mother of four from Macomb, Michigan, received a life-changing diagnosis at age 23: Mosaic Down's syndrome, a rare form of Trisomy 21 where only some cells carry the extra chromosome. The diagnosis came after her third child was born with the condition, prompting her gynecologist to suspect an underlying genetic factor.
Diagnosis after three pregnancies
Zambelli's first pregnancy in 2019 ended in a missed miscarriage, and genetic testing on the tissue revealed the baby had Down's syndrome. Her second daughter, Lillian, now five, also tested positive for Trisomy 21, as did her third daughter, Katherine, now three. 'The third time it happened with Katherine, alarm bells started ringing for my OBGYN, as she'd never had a patient with that many positive results before,' Zambelli told Metro.
Her doctor referred her to a genetic counselor who ran blood tests, which initially showed no abnormalities. However, a buccal smear test—swabbing the inside of the cheek—finally confirmed the diagnosis. Zambelli learned she has Mosaic Down's syndrome, meaning up to 20% of her cells have an extra chromosome.
Relief and validation
Far from being upset, Zambelli felt overwhelming relief. 'I was so happy when they gave me that diagnosis—it was finally an answer that I could add to my medical chart and use it to get the help I needed,' she said. The diagnosis explained a lifetime of health issues, including an abnormally high heart rate, dislocating joints, and learning difficulties in school.
She recalls the moment she found out while at the hospital with her daughter Lillian: 'I've never seen so much concern on somebody's face. She didn't understand why I was so pleased to have been diagnosed with Down's syndrome.'
Understanding her children
The diagnosis has deepened her bond with her children who have Down's syndrome. 'I almost feel like I can understand more of what they are going through and how their brain processes things—it takes me longer to process things too, so I can just relate with them a little better,' she explained.
Mosaic Down's syndrome accounts for about 2% of all Down's syndrome cases, but the actual number may be higher due to underdiagnosis. Research indicates that individuals with Mosaic Down's syndrome may exhibit fewer characteristic features than those with other forms.
Challenges in healthcare
Despite the clarity, Zambelli has faced skepticism from some medical professionals. 'It's been harder than I thought to get help for some of the symptoms I'm experiencing, because now everything is just chalked up to my diagnosis. Everything is blamed on Mosaic Down's syndrome,' she said. 'Some doctors also completely brush me off and don't believe I have Down's syndrome.'
She has been told she doesn't have 'real' Down's syndrome or look 'Down's syndrome enough' because she lacks typical facial features. Her only physical trait is smaller, lower-set ears, which are often unnoticed.
Raising awareness
Zambelli now shares her story on TikTok and Instagram to raise awareness. She receives messages from doctors and nurses who admit they knew nothing about the condition. 'The main doctor I see for checkups wasn't even aware that Mosaic Down's syndrome was a thing,' she said.
Her content has even been used in biology classes by professors, which she finds surreal. 'I feel honoured, but I can't believe people are watching my videos in classes. I'm not a doctor, I don't have a degree in science or biology, I'm just sharing my own experience,' she added.
