Cal. Three years have passed since I published “Mothering Cal” in Slate, just before Mother’s Day 2013. It had been 11 months since my daughter Cal was diagnosed with leukodystrophy, a fatal degenerative brain disease. Cal is named after the muse Calliope, the goddess of music whose divine power is to inspire beauty in the world. The last time Cal would sing for me would be in the hospital, two days before a brain MRI revealed Cal had metachromatic leukodystrophy, or MLD. It is one of 50 forms of leukodystrophy affecting 1 in 5,000 people (making it more common than ALS, the neurological disease that inspired the 2014 ice bucket challenge). MLD is a diagnosis so grim that back then, all the neurologist at the Children’s Hospital of Philadelphia could do for us was arrange for a Make-a-Wish vacation. MLD would rob Cal of the ability to speak, walk, and eat within three months. This monstrous disease is caused by a faulty gene that controls a protein needed to keep our nerves intact. The disruption leads to a breakdown in communication between the nervous system and the brain. Cal was 2 when she was diagnosed; the genetic counselor working with us told us that most children with this form of the disease do not live more than four years after the symptoms start to show. It would take me years to understand that grief is a metamorphosis: The pain must change you. Cal is now 6 years old. We are in overtime with this disease. In that first year after Cal’s diagnosis, the madness of grief consumed me. There was nothing anyone could do or say to “make it better,” so all the people who loved me could do was witness a series of miniature nervous breakdowns that ranged from the heartbreaking (fits of crying so intense they made me choke and vomit) to the absurd (writing letters to Adam Sandler asking him to sing a song he performed on “Sesame Street” for Cal’s fourth birthday). It would take me years to understand that grief is a metamorphosis: The pain must change you. There is no way to escape losing a sense of who you once were. And after a year (or two), you wake up from this transformation and realize that you were not actually dying; you just felt like you were. And then you must make a choice. One option: You can give into the horror of it all and retire to bed. No one would blame you; it is a tempting alternative that lurks at the back of my brain from time to time even now. The other option is that you take the pain and harness it to do things you could not imagine ever possessing the strength to accomplish. Being around children like my daughter will teach you the very meaning of life. The first thing Cal showed me was there was no time to mourn the life we had expected. My children, husband, and I have a form of amnesia about our old life, when Cal could walk and talk and stuff her face with meatballs. Short visits to our old life are permitted, but we cannot lose ourselves in our fury and despair by imagining how things were supposed to be. Living with leukodystrophy requires an unforgiving discipline. As the disease takes more and more from you, you must find joy and happiness in what it cannot take. Three years ago, a good day was an afternoon in the pool or a walk to the park. Now it is a day with no seizure activity and making Cal smile at least once. It astonishes me that I find joy in simple moments, such as watching my son practice his guitar for his little sister or marveling at my oldest daughter reading Eric Carle’s “The Very Busy Spider” (and even doing all the animal sounds) to Cal. My husband, children, and I have worked very hard to create a normal life. Normalcy requires banishing pity from our lives. Normalcy was not what it had been before leukodystrophy, but with the hospice nurses, doctors, social workers, and our friends and neighbors, we have figured out a way to go to school and work and celebrate the holidays. Even the medical equipment that replaced Cal’s toys could not undermine our pursuit of this normal life. Sometimes the siblings of children with a terminal illness feel compelled to be perfect children to shield their parents from any more worry. So I am relieved when my children whine about dinner and argue with me about doing their homework, because their sister’s illness should not mean they cannot be kids with normal problems and feelings. We even got a dog. The head of the nursing team worried that a dog might alter the ecosystem of normalcy in our house. But the dog, an adopted bichon named Brody, sleeps with Cal and taught himself to bark when she has seizures. He takes the edge off life for my older children and even makes me get my daily 10,000 steps with long walks on the beautiful nature trail near our home in suburban Philadelphia. Dogs really do make everything better. My daughter has taught me when the worst possible thing happens, you have nothing left to fear. She has taught me that fearless people are maddening and relentless, and if we are fortunate, we can find a way to honor our children by changing the world. She has taught me that when you have tamed your fear, you harness its power to do extraordinary things. In the end, the only way to save yourself from the grief is to find a way to help other families. So what could a family caring for a terminally ill child do to help other people? It sounds nuts, but we started selling cupcakes for $1 each. My children and I live in the community where the late cancer patient Alex Scott reinvented cancer research fundraising with a lemonade stand. And so when my 8-year-old son suggested we could sell cupcakes to help kids with leukodystrophy, we had a role model in the Scott family. We sold cupcakes in parking lots, church halls, school playing fields, and one time at a street festival when six inches of snow fell over two hours. It was hard to talk about Cal and explain a rare disease that most people knew nothing about. In fact, we had never heard of MLD before Cal’s diagnosis. My husband and I were completely shocked, therefore, to discover that we were both carriers of the dormant gene that triggered it. This meant that all of our children had a 1-in-4 chance of inheriting MLD and a 1-in-2 chance of being carriers like us. The cupcakes helped us raise awareness of leukodystrophy and build a supportive community. It would not take long for the cupcakes to become a real charity . In 2013, our friends and neighbors at the school where Cal would have attended kindergarten this fall hosted a whole daylong celebration of cupcakes called Cal’s Cupcake Challenge. Eight hundred people attended, and we raised $9,000. Nine thousand dollars is not a great deal of money for rare disease research. But what we did with that money changed everything. In 2013, Dr. Alessandra Biffi (now the director of gene therapy at Boston’s Children’s Hospital) published unprecedented results of a gene therapy trial in the prestigious journal “Science.” The treatment, pioneered in children with MLD, is already saving lives and is proving to be a game-changer. Dr. Biffi and her team are replacing the faulty gene that causes MLD with a working copy of that gene. Since naked DNA cannot be directly injected into our cells, the scientists use a virus to deliver the new genes. Viruses have naturally evolved to infiltrate our cells and deliver their genetic payload into the very heart of them. Therefore, the researchers have gutted a virus of its harmful genes but kept the useful ones intact. Dr. Biffi first withdraws the patient’s own stem cells in an operation similar to a bone marrow transplant. These cells are then exposed to the modified viruses, which, in effect, infects them with the functioning genes. The patient’s corrected cells are then re-infused into their bone marrow, and gradually they start to produce the crucial protein needed to keep our nervous system intact. Once upon a time, this research sounded like science fiction, but today doctors at the Children’s Hospital of Philadelphia and research centers all over the world believe gene therapy could defeat leukodystrophy within the next decade. Children who otherwise would be nonverbal and paralyzed are riding bicycles and attending school. Cal would never have benefited from gene therapy, because the treatment can only prevent damage to the brain; it cannot reverse the process once the disease starts. One day, newborn screening via a heel-prick blood test will find children with leukodystrophy at birth. Cystic fibrosis and Tay-Sachs are among the few dozen genetic conditions currently screened for in newborns, but there are hundreds of other fatal, rare diseases that are not part of the standard newborn or prenatal testing. That is why the children Dr. Biffi treated were so very special. In every case, like us, the families only found out about MLD when their child was diagnosed. By this stage, as with Cal, the disease will have progressed past the point of treatment—but it will also raise the possibility that their other children, even those who had no symptoms, could also have MLD. Caught early enough, gene therapy can prevent MLD. Even if MLD took an older child, it would mean that his or her younger sibling would be eligible for Dr. Biffi’s trial. The doctor who diagnosed Cal, Dr. Amy Waldman at the Children’s Hospital of Philadelphia, suggested that we use the money we raised from selling cupcakes to help another child with MLD fly to Milan for this treatment. When Dr. Waldman proposed this, I was astounded. It had been impossible to imagine helping other families when Cal could not be saved. But in August 2014, we got our chance to help a family in Omaha, Nebraska, travel to Milan with their 1-year-old. We packed a care package of a new iPad, toys, and blankets, and a check of $2,000 to help with expenses. The family had lost one child to the disease the year before. The baby would become the 10 th child in the world to undergo the treatment in Milan. In the past two years, the foundation we created in Cal’s name and the cupcakes we sell in a school playground have helped five families and their pursuit of miracles. It’s possible that children all over the world will have a chance to do all the things I dreamed of for Cal — going to school, dancing in a recital. Helping these children is our investment in a miracle. And Dr. Biffi’s research continues to live up to its promise — five years after treatment, Giovanni Price, the second child treated in Milan, started kindergarten. I have had the chance to spend time with three of the children, and two of them have attended Cal’s Cupcake Challenge and have met Cal. Because of the cupcakes, we are now working with researchers and doctors to get this revolutionary new therapy to the United States as quickly as possible. Cal’s neurologist, Dr. Waldman, now leads a Leukodystrophy Center at the Children’s Hospital of Philadelphia. There, leukodystrophy is no longer an orphan disease — instead it is a major initiative, with 35 specialists and researchers championing these children. On a few days a year — such as Cal’s birthday or the anniversary of her diagnosis — I allow myself to imagine the future I had wanted for my daughter. Helping other people’s children will never be enough to make up for losing Cal. My deepest wish is still that I had never heard of leukodystrophy, that my 6-year-old daughter would be running around my house and driving us all crazy. The thing is, until Cal, I didn’t understand miracles. We don’t get miracles because we wish for them or even pray for them — miracles must be earned through sacrifice, hard work, and struggle. In these past three years, my daughter has helped me realize the profound gift of witnessing a miracle and playing a very small part in creating one. This post originally appeared here on Slate We want to hear your story. Become a Mighty contributor here .