Identical twin given six months to live says leaving sister is ‘unthinkable’
Caitlin, Identical Twin Given Six Months to Live, Says Leaving Sister is 'Unthinkable'
Identical twin given six months to live - Caitlin Leggett, a 24-year-old from Cardiff, has been diagnosed with a recurrence of acute myeloid leukaemia (AML) and given a six-month survival prognosis. The news has left her devastated, as the thought of being separated from her identical twin sister Grace is described as "unthinkable." Diagnosed in April 2025, Caitlin initially noticed only a persistent rash as a sign of her illness. After a period of remission following chemotherapy, the cancer returned in May, limiting her treatment options in the UK.
The Twin Connection and Genetic Discovery
Despite their close bond, Caitlin and Grace were not aware they were identical twins until Caitlin’s diagnosis prompted medical tests. Initially believed to be fraternal due to their separate amniotic sacs, the sisters’ genetic markers matched perfectly when Grace was considered a stem cell donor. This discovery complicated Caitlin’s treatment plan, as Grace’s identical DNA meant she could no longer donate her cells. The revelation deepened the emotional weight of the situation, as the sisters now faced the possibility of being apart for the first time in their lives.
A Medical Timeline of Hope and Uncertainty
Caitlin had ambitious plans for her future, including joining the Army and training as an intelligence officer after graduating in July 2024. Her medical evaluation, originally scheduled for April 2025, revealed a critical turning point when a rash she developed in March failed to respond to over-the-counter treatments. Blood tests confirmed the severity of her condition, leading her to the Teenage Cancer Trust unit at the University Hospital of Wales. The diagnosis not only altered her treatment path but also shifted her focus from career goals to survival.
Following chemotherapy, Caitlin achieved remission in May 2025. However, the cancer reappeared on her skin by August, necessitating a clinical trial in Manchester using menin inhibitors. This treatment temporarily placed her in complete remission before a stem cell transplant was planned for December 2025. Unfortunately, the leukaemia returned just a week before the transplant, requiring additional full-body radiotherapy. Caitlin was once again declared in remission in January 2026, though her doctors now emphasize the importance of regular bone marrow checks to monitor her condition.
Caitlin’s prognosis remains uncertain, with monthly bone marrow checks recommended for the next three months and quarterly assessments from March 2026. The sisters have made it clear that the idea of being separated for six months is "unthinkable," as their bond has always been central to their identity. Caitlin insists on an extra test in May, which will determine whether her cancer is in remission or has returned. If the results are not favorable, she will continue her current drug trial for Bleximenib, with a backup plan involving another trial if needed.
The six-month survival estimate has pushed Caitlin and Grace to seek curative options abroad. While the UK offers limited treatments, Caitlin is exploring specialized leukaemia therapies in the US and innovative immunotherapy approaches like CAR-T cell therapy in China or Singapore. These international treatments could cost up to £500,000, prompting the sisters to launch a fundraising campaign to cover the expenses. Their efforts reflect not only a determination to fight the disease but also a refusal to accept the prospect of losing their twin connection.
Caitlin’s story has resonated with many, highlighting the unique challenges faced by identical twins in the face of illness. The emotional and logistical strain of her condition has brought their relationship into sharp focus, with Grace expressing her unwavering support and commitment. "We're only 24—nobody expects this to happen," Grace said. "Being twins as well, you're not supposed to have one twin not be there." As Caitlin continues her treatment journey, the twin’s bond remains a source of strength and hope in their battle against leukaemia.