Chromosome Deletion

Like most first time mothers, Diane read books to better understand her baby Madeleine's early development stages. At around 6 months, she suspected something was wrong with Maddie because she was not yet able to hold her head up. Inconclusive medical testing, which included sonograms, an EKG, and blood work, finally led to an optometrist who identified an optical nerve abnormality in Maddie's left eye. This abnormality was potentially related to her brain, so Maddie was examined by a neurologist, who then recommended that she be taken to a geneticist. At this point, Maddie was 2 years old and was exhibiting other symptoms of developmental delay, including low muscle tone.

It was the geneticist who called for a new test known as the FISH test, an acronym for "Fluorescence in situ hybridization." At that time, it was the doctor's first FISH test that she had ever administered—although now they are given quite regularly. Diane describes the test as shooting light through the chromosome. If the light doesn't bounce back, the doctors know that part of the chromosome is missing, which is known as a deletion. Although two other chromosome tests had previously come back normal, the FISH test was able to detect Maddie's disorder.

Diane had trouble understanding the diagnosis until the geneticist explained. "It's like a library that has all of the books, but one of them is missing a page," said the geneticist.

Maddie is now 6 years old and although she is barely walking and still not talking, Diane and her husband have learned much about her condition thanks to the diagnosis from the FISH test. The test results not only gave them direction in gathering information, but also helped them to narrow down Maddie's treatment options. Maddie continues to get retested on an annual basis to monitor her progress and to help physicians and the family learn more about her deletion. The family is optimistic, as Maddie seems to grow ever more cognitively engaged.