Greg’s journey with LMNA cardiomyopathy, a rare inherited heart condition, began in high school when he experienced sudden episodes of rapid, irregular heartbeats during track practice. The cause remained a mystery for years, leading to misdiagnoses and untreated disease progression. During that time, Greg faced life-threatening arrhythmias and required several implanted devices before finally receiving a heart transplant. That experience, and the challenges that came before it, ultimately inspired his passion to create change and help others facing the same uncertainty. In this episode of On Rare, David Rintell, Head of Patient Advocacy at BridgeBio, and Mandy Rohrig, Senior Director of Patient Advocacy at BridgeBio, speak with Greg about the long road to diagnosis, the emotional impact of learning he had passed the condition on to his children, and his transformation into an advocate as president of the DCM Foundation. He also shares how his personal experience led to the launch of Everygene, a free genetic testing program for people with cardiomyopathies.

Dr. Clayton Beard, Chief Scientific Officer at BridgeBio Gene Therapy, provides a high-level medical overview of LMNA-related dilated cardiomyopathy, a form of heart disease caused by mutations in the LMNA gene that compromise the structural integrity of heart cells and disrupt electrical signaling. He explains how these changes can cause dangerous arrhythmias, weaken the heart muscle, and lead to heart failure, making LMNA cardiomyopathy one of the most severe genetic forms of the condition. Dr. Beard also highlights the importance of early genetic testing for at-risk families, the role of research in improving detection and treatment, and how a better understanding of LMNA can lead to life-saving interventions.

Before she turned eight, Cerys had already faced two diagnoses, only one of which she truly understood. While being diagnosed with celiac disease as a child, unusually high CK levels in her blood pointed to a deeper issue: limb-girdle muscular dystrophy type 2I/R9 (LGMD2I/R9). In this 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 Cerys, a 23-year-old living in Wales, about living with LGMD2I/R9. She shares how she’s navigated symptom progression, adapted to using mobility aids, and discovered the power of telling her story through her podcast, Unbalanced. When Cerys was first diagnosed with LGMD2I/R9 at age seven 7 years old, she didn’t fully understand the diagnosis. Her parents carried the emotional weight, trying to protect her from fear of what was ahead. It wasn’t until her muscle weakness became impossible to ignore, at 12 years old, that the condition began to define her daily life. From navigating stairs and driving to embracing a wheelchair, Cerys has had to adapt physically, emotionally, and socially, all while managing her energy levels so that she can continue to do the activities she loves. She finds strength in the LGMD community and hope in research, representation, and connection. In 2023, she launched Unbalanced to amplify stories like hers because growing up, she didn’t see anyone with a disability who looked like her. Now, she’s determined to be that voice for others.

Dr. Anna Talaga, Director of Medical Affairs at ML Bio Solutions (a BridgeBio affiliate), provides a medical overview of LGMD. LGMDs are a group of genetic diseases that cause progressive muscle weakness and wasting, particularly in the shoulders, hips, and thighs. In some people, the heart and respiratory muscles may be impacted. Unlike many genetic conditions that are caused by a mutation in a single gene, LGMD can result from mutations in many different genes because they all affect the same protein complex that supports and stabilizes muscle fibers. LGMD type 2I/R9 (LGMD2I/R9), specifically, is caused by mutations in the FKRP gene, which is critical for maintaining muscle fiber integrity. Diagnosis typically begins with symptoms like difficulty walking, climbing stairs, or standing from a seated position, and is confirmed through genetic testing. LGMD2I/R9 is a progressive disease and there are currently no approved treatments that slow or stop its progression.

Seizures, sleepless nights, and mysterious white patches on his skin marked the beginning of Daniel’s journey with Tuberous Sclerosis Complex (TSC). Diagnosed at age 6, Daniel faced a childhood filled with MRIs, EEGs, and specialist visits, often requiring cross-country travel for coordinated care. 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 Daniel, a 31-year-old living in Seattle, about growing up with TSC, the emotional toll of visible symptoms, and the stigma he faced from peers. He reflects on the cognitive and mood impacts of TSC, including OCD and outbursts, and how he often kept to himself to feel more accepted. Today, Daniel is an active advocate in the TSC community, emphasizing the importance of connection, representation, and finding support among those with shared experiences. As he puts it, “You have to find your people.”

Che-Wei Chang, Principal Scientist at BridgeBio, presents a medical overview of Tuberous Sclerosis Complex (TSC), a rare genetic disorder marked by seizures and benign tumors throughout the body. TSC results from a spontaneous mutation in a single copy of the TSC1 or TSC2 gene, which normally inhibit mTOR, an enzyme that regulates cell growth. Loss of this inhibition leads to mTOR hyperactivation, leading to abnormal cell proliferation and tumors in the brain, kidneys, skin, and other organs. Diagnosis typically involves identifying tubers in the brain along with tumors in other organs and is confirmed through genetic testing. Treatments include mTOR inhibitors, which are effective against many TSC-related tumors, and anti-seizure medications, although drug resistance is common.

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.