“We just thought we were clumsy”. Katie and Allie are living with late-onset Tay-Sachs disease

Katie and Allie’s story began in childhood with unexplained clumsiness and subtle symptoms that intensified over time. After years of searching for answers, Katie was diagnosed with late-onset Tay-Sachs (LOTS), a rare neurodegenerative disease. Further testing confirmed her twin sister Allie’s diagnosis as well. Despite facing daily challenges ranging from mobility issues to emotional strain, the sisters have become passionate advocates, raising over $1 million for research and awareness. With humor, grit, and the support of their family—especially their powerhouse mom—they continue to live fully and inspire the rare disease community. In this moving episode of On Rare, David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Senior Director of Patient Advocacy at BridgeBio Gene Therapy, speak with Katie and Allie, who share their experience with late-onset Tay-Sachs. The episode explores how Tay-Sachs, typically diagnosed in childhood, can present in adulthood, the emotional toll of navigating a progressive rare disease, and the resilience of a close-knit sibling duo who’ve turned advocacy into action.   Diana Jussila, Director of Family Services at the National Tay-Sachs & Allied Diseases Association (NTSAD), provides essential insights into late-onset Tay-Sachs disease, a rare, progressive, neurodegenerative condition caused by mutations in the HEXA gene leading to deficiency of the Hex A enzyme. Without this enzyme, toxic substances accumulate in the brain and spinal cord, resulting in symptoms like muscle weakness, balance issues, speech difficulties, and psychiatric challenges. With no approved treatments and only supportive care available, community connection, advocacy, and ongoing research are vital lifelines for those living with late-onset Tay-Sachs disease.

Philip’s journey with ATTR began with unexplained weight loss and gastrointestinal issues that puzzled doctors for years. Despite seeing multiple specialists, his condition remained undiagnosed until a physician at Johns Hopkins finally connected the dots, confirming ATTR. By then, Philip had lost 60 pounds and was on the brink of survival. In today’s episode of On Rare, David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Senior Director of Patient Advocacy at BridgeBio Gene Therapy, speak with Philip and his wife, Sally, who has helped to navigate the frustrating medical system, advocate for answers, and ultimately helped Philip receive life-saving IV nutrition. After years of uncertainty, Philip finally found an expert team with the knowledge, treatment, and community they needed. Philip and Sally share their story of perseverance, partnership, and hope for a brighter future. Dr. Adam Castaño, head of the Amyloid Prevention Program at BridgeBio, provides a medical overview of TTR amyloidosis (ATTR), a rare, progressive disease caused by misfolded transthyretin (TTR) proteins that form amyloid deposits in different parts of the body such as the heart, the peripheral nervous system, and the gastrointestinal tract. These deposits lead to debilitating symptoms including heart failure, neuropathy, and digestive issues, often mimicking common age-related conditions and possibly contributing to underdiagnosis. ATTR can be hereditary, but it also develops in the general population (this is called wild type). Advancements in non-invasive imaging and specialized protein staining have improved early detection, offering hope for better disease management.

When Julien was just 6 weeks old, Kady knew something wasn’t right. Despite more than 16 doctors insisting Julien was fine, Kady trusted her instincts and fought for answers—refusing to leave the hospital until the right tests were done. That persistence led to a life-changing diagnosis: a rare genetic form of hypoparathyroidism. Julien’s specific mutation is so unique that he is the only known case in the world. In today’s episode of On Rare, David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Director of Patient Advocacy at BridgeBio Gene Therapy, speak with Kady, the mother of Julien, a 4-year-old boy living with ADH1. Managing his condition has been a daily balancing act, as too little calcium leads to painful, debilitating symptoms, while too much threatens his kidneys. Kady shares the emotional journey of raising a child with a rare disease, from relentless advocacy to empowering Julien with the knowledge to recognize and communicate his own symptoms.   Michael Collins, M.D., a research scientist at the National Institute of Health (NIH), provides a medical overview of Autosomal Dominant Hypocalcemia Type 1 (ADH1), a rare form of hypoparathyroidism that leads to low blood calcium levels. While most cases of hypoparathyroidism result from accidental gland removal during thyroid surgery, ADH1 is caused by genetic mutations. Often going undiagnosed until a child presents with severe symptoms, ADH1 is difficult to catch early since calcium levels are not part of routine pediatric screenings. The condition is also difficult to treat because standard calcium supplements, which alleviate ADH1 symptoms, can worsen kidney complications, increasing the risk of severe kidney stones and even renal failure. Treatment requires a delicate balance to avoid overcorrection and long-term kidney damage. Dr. Collins sheds light on the complexities of this condition and the challenges both patients and doctors face in managing it.

In our final episode of 2024, On Rare looks back at highlights from the rewarding and rare conversations with our exceptional guests and David Rintell, Global Head of Patient Advocacy at BridgeBio and Mandy Rohrig, Director of Patient Advocacy at BridgeBio Gene Therapy. We listened, we learned, we laughed, and we cried. We are deeply grateful to all of our guests. Join us for a look back at 2024 and don’t forget to subscribe to learn more from our guests in 2025.  

Charles, a recently retired cardiologist of 53 years, speaks with David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Director of Patient Advocacy at BridgeBio Gene Therapy, about how his unexpected early diagnosis of ATTR-CM likely impacted the trajectory of his disease. Dr. Jonathan Fox, President and Chief Medical Officer of cardiorenal programs at BridgeBio, explains how ATTR affects the heart and peripheral nervous system, and the importance of early diagnosis.   For years, Charles suffered from numbness and tingling in both wrists and hands. Eventually, when the pain became so severe that operating a mouse for 10 to 15 minutes was difficult, he was referred to a hand surgeon who recommended carpal tunnel surgery. Preparing for the surgery, Charles recalled reading a medical journal article that indicated 10% of people who underwent carpel tunnel surgery had positive tissue biopsy indicative of ATTR-CM. He requested that his surgeon perform a biopsy and shortly thereafter received his diagnosis. The transition from doctor to patient was not easy for Charles. However, he feels fortunate to be a cardiologist, to have read and remembered the article, requested a biopsy, and received the diagnosis more quickly than many others who live with ATTR. “I have three passions: running, traveling, and teaching," Charles shared. The early diagnosis has allowed him to continue to live a full, active life, running nearly daily as he has for the past 45 years. Charles, now 86, continues to serve others, spending his retirement teaching and mentoring health care providers around the country about ATTR and volunteering for amyloidosis advocacy organizations.

Erin joins David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Director of Patient Advocacy at BridgeBio Gene Therapy, to share her experience living with hypochondroplasia. Erin also has two sons living with hypochondroplasia and one son of average height. Raised in a loving and supportive family with a can-do attitude, her father told her that she may be of short stature but that she could do everything she wanted to do, just maybe in a slightly different way. Erin shares her diagnostic journey with hypochondroplasia in the third grade. Even though her diagnosis was upsetting to her, her friends and family never treated her any differently. She describes her decision to undergo limb-lengthening surgery, how she manages her condition, and discusses how her two sons navigate living with hypochondroplasia in very different ways. While there were times when Erin would have preferred to be just like everyone else, she has learned the value of embracing individuality and the importance of family and finding fulfillment in life. Elena Muslimova, Medical Director of the hypochondroplasia program at QED Therapeutics, a BridgeBio affiliate, provides a medical overview. She explains that hypochondroplasia is a rare genetic bone condition causing short stature with an average-sized trunk but shorter arms and legs. It often arises from de novo (spontaneous) mutations, yet it can also be inherited. Hypochondroplasia is typically diagnosed in children aged 2 to 5 years old. While short stature is the primary characteristic, individuals may experience other complications although the severity of these issues varies greatly among individuals.  

In today’s episode of On Rare, David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Director of Patient Advocacy at BridgeBio Gene Therapy, speak with Misty about her experience living with limb-girdle muscular dystrophy, type2I/R9 (LGMD2I/R9). Misty details the suffering she experienced in her childhood from bullying for the symptoms she now realizes are connected to LGMD2I/R9 and shares the many frustrations and significant challenges that resulted from her delayed diagnosis. Despite noticing alarming symptoms as early as junior high school, Misty was dismissed by medical professionals for years. Finally, and only after both her younger twin sisters were diagnosed with LGMD2I/R9, Misty received her own genetic confirmation of LGMD2I/R9. She was 32 years old. Receiving her diagnosis was like an emotional tornado, and immediately, Misty feared that she may have passed LGMD2I/R9 on to her children. Throughout her journey, Misty has tried to hold on to the positives. She talks about the creative ways she has adapted to life with a progressive disease and emphasizes the importance of showing oneself grace and finding community.   Ada Lee, M.D., Medical Director at ML Bio Solutions, a BridgeBio company developing BBP-418 for LGMD2I/R9, provides an overview of the genetic condition. She explains that limb-girdle muscular dystrophy (LGMD) is an umbrella of diseases associated with progressive muscular weakness in the girdle muscles, some of the central muscles that support limbs. LGMD2I/R9 (also called “LGMD R9 FKRP-related”) is a genetic disease caused by a mutation in the FKRP gene. The FKRP gene is involved in helping muscles build a glycoprotein called alpha-dystroglycan. When the gene doesn’t work correctly, it causes damage to muscle tissue, and over time, develops into scar-like, fibrotic tissue. As fibrotic tissue overtakes healthy muscle tissue, muscle strength and function declines, and people living with LGMD2I/R9 lose the ability to perform routine daily activities unassisted—such as walking or standing up. Many people with LGMD2I/R9 have prolonged pathways to diagnosis because it is a rare disease with an early onset of symptoms.   To learn more about LGMD2I/R9 and the LGMD community, visit the LGMD Awareness Foundation, the CureLGMD2i Foundation, and The Speak Foundation.

In this emotional episode of On Rare, David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Director of Patient Advocacy at BridgeBio Gene Therapy, speak with Dawn, the single parent of Vayle, a 5-year-old girl living with Canavan Disease. Dawn shares how she came to realize that Vayle was not meeting developmental milestones at 3-4 months old. Despite initial reassurance from her pediatrician, Dawn’s maternal intuition proved correct, leading to a diagnosis of Canavan Disease during Vale’s 6-month checkup. Dawn was told that Vayle might not live beyond the age of ten. Dawn recounts the emotional challenges of adapting to the diagnosis, while learning how to manage Vayle’s increasingly complex medical and care needs. Even with the expectation of a shortened life, Dawn emphasizes the profound love and quality of life she and Vayle share, underscoring her deep commitment to making Vayle's life as comfortable and joyful as possible. Dawn hopes that telling Vayle’s story can bring awareness to this rare disease and help other families going through similar circumstances. This, she hopes, will be part of Vayle’s legacy. Dr. Dominic Gessler, a physician and researcher who has extensively studied Canavan Disease explains that Canavan Disease is an autosomal recessive genetic disorder caused by mutations in the ASPA gene, leading to the accumulation of a chemical called N-acetyl-L-aspartic acid, or NAA, throughout the body. The accumulation of NAA is thought to damage the white matter in the brain.  Symptoms of Canavan disease become apparent as children fail to meet developmental milestones. As always, questions about your healthcare and the healthcare of your family should be discussed with your physician.

Sean joins David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Director of Patient Advocacy at BridgeBio Gene Therapy to share his journey with ATTR. In this episode, Sean describes his initial symptoms, which included carpal tunnel syndrome and numbness in his foot and ankle, the misdiagnosis he experienced, and his eventual diagnosis at the Cleveland Clinic in Abu Dhabi. While the diagnosis was a relief it was also difficult to accept and took an emotional toll on him and those around him. Sean has found this to be a common experience of many diagnosed with ATTR. Since Sean’s form of ATTR is hereditary, various members of his family have also been tested. Sean also highlights the positive changes in his life, including meeting his wife, Robin, discovering a talent for drawing, and becoming a public speaker about ATTR. Jonathan Fox, President and Chief Medical Officer of cardiorenal programs at BridgeBio, joins us again to give a medical introduction to ATTR. On this episode, Jonathan highlights the differences of the ATTR T80 variant. Previously, we learned that ATTR amyloidosis is caused by the dissociation of a protein called transthyretin, or TTR, that changes its shape and forms into fibrous clumps. These clumps of misshapen protein are deposited into various organs and peripheral nerves, including the heart, which can cause them to function abnormally. Jonathan explains the possible origin of the T80 variant and how the T80 variant symptoms can differ from ATTR-CM.   To learn more about living with amyloidosis visit Mackenzie's Mission, www.mm713.org

Alex joins David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Director of Patient Advocacy at BridgeBio Gene Therapy, to speak about her son, Hudson. Before Hudson’s birth, Alex and her husband learned that Hudson would be born with hypochondroplasia. A genetic counselor helped her to understand the diagnosis. Although Alex is a medical professional, she had never heard of this condition, and the many unknowns of this new diagnosis left Alex feeling scared. However, all these fears were put aside when she held Hudson for the first time. At five days old, Hudson had breathing problems and Alex had to perform CPR on him. Hudson was later diagnosed with severe obstructive sleep apnea and needed to be on oxygen therapy. Alex describes the learning curve that she and her husband experience as they learned to care for Hudson and anticipate some of his early medical needs. Now at 20-months-old, Hudson is a happy little boy who loves to read, walk, and babble, and is adored by his older sister. Teja Reddi, Ph.D., a Senior Director of Strategy and Operations of Skeletal Dysplasias at BridgeBio, explains that although hypochondroplasia is a milder form of dwarfism than achondroplasia, the condition can cause some medical complications. Hypochondroplasia is a skeletal dysplasia characterized by short stature; stocky build; disproportionately short arms and legs; broad, short hands and feet; mild joint laxity; and macrocephaly. Teja also talks about the challenges of underdiagnosis and the hope for more research to improve the lives of people with hypochondroplasia. Please note, the views and opinions expressed in this episode of On Rare are those of Alexandra and do not necessarily reflect the official policy or position of BOLDSCIENCE.