Rare Diseases: Study Notes

General Science July 28, 2025 5 min read

Definition and Scope

Rare diseases (also called orphan diseases) affect a small percentage of the population. In the US, a disease is considered rare if it affects fewer than 200,000 people.
Over 7,000 rare diseases have been identified, collectively impacting millions globally.
Analogous to rare species in an ecosystem—each rare disease is unique, often requiring specialized attention and resources.

Finding a Rare Disease: Like searching for a specific grain of sand on a vast beach—most grains are similar, but the rare one requires close inspection and special tools.
Treatment Development: Comparable to designing a custom key for a unique lock; mass-produced keys (common treatments) won’t fit, so bespoke solutions are needed.

Huntington’s Disease: A genetic disorder causing progressive brain degeneration.
Gaucher Disease: A metabolic disorder due to enzyme deficiency, affecting organs and bones.
Progeria: Causes rapid aging in children, with fewer than 400 cases worldwide.

Description: FOP is a rare genetic condition where soft tissues (muscles, tendons) gradually turn into bone, restricting movement.
Prevalence: ~1 in 2 million people.
Real-World Impact: Patients may become “locked” in their bodies, similar to how a tree’s branches become rigid as it grows.
Diagnosis Challenge: Often mistaken for cancer or other bone disorders, leading to unnecessary biopsies or surgeries.
Recent Research: According to Kaplan et al. (2021, Nature Reviews Disease Primers), advances in genetic sequencing have identified the ACVR1 gene mutation as the cause, paving the way for targeted therapies.

Analogy: Just as rare bacteria thrive in deep-sea vents or radioactive waste—environments hostile to most life—rare diseases can present in ways that defy typical medical expectations.
Example: Deinococcus radiodurans survives radiation; similarly, rare diseases sometimes persist undetected in the population, resistant to standard diagnostic methods.
Implication: Studying extremophile bacteria has inspired novel diagnostic tools (e.g., robust enzymes for genetic testing), which are now used to identify rare disease mutations.

Delayed Diagnosis: Average time to diagnosis is 5-7 years, often involving multiple specialists and misdiagnoses.
Limited Awareness: Many healthcare professionals encounter rare diseases infrequently, leading to gaps in knowledge.
Genetic Testing: Advances in whole-exome and whole-genome sequencing have improved identification but remain costly and inaccessible in many regions.

Gene Editing (CRISPR): Offers potential for correcting disease-causing mutations. Example: Ongoing trials for sickle cell disease, which, while not rare globally, is rare in some regions.
Artificial Intelligence: Machine learning algorithms analyze patient data to detect patterns that signal rare diseases earlier than traditional methods.
- Reference: Topol, E.J. (2020), “High-performance medicine: the convergence of human and artificial intelligence,” Nature Medicine.
Telemedicine: Connects patients with rare diseases to global experts, overcoming geographic barriers.
Biomarker Discovery: Using proteomics and metabolomics to find unique biological signatures for rare diseases.

Misconception 1: Rare diseases only affect a few people, so they’re not important.
- Fact: Collectively, rare diseases affect over 350 million people worldwide.
Misconception 2: Rare diseases are always genetic.
- Fact: While many are genetic, some result from infections, environmental exposures, or unknown causes.
Misconception 3: There are no treatments for rare diseases.
- Fact: Treatments exist for some rare diseases, but access and research funding are limited.
Misconception 4: Rare diseases are the same everywhere.
- Fact: Prevalence can vary by region due to genetic, environmental, and cultural factors.
Misconception 5: Rare diseases are always fatal.
- Fact: Many rare diseases are chronic but manageable with proper care.

Social Isolation: Patients often feel isolated due to lack of understanding from peers and medical professionals.
Financial Burden: High costs for diagnosis, treatment, and supportive care.
Research Funding: Pharmaceutical companies may not invest in treatments due to small market size (“orphan drug” status).

2022 News: The FDA approved Zolgensma, a gene therapy for spinal muscular atrophy (SMA), a rare neuromuscular disease. This therapy uses viral vectors to deliver functional genes, demonstrating the promise of gene therapy for rare conditions.
- Source: U.S. Food & Drug Administration, “FDA Approves Innovative Gene Therapy for SMA,” 2022.

Awareness Campaigns: Organize events to educate peers about rare diseases.
Collaboration: Partner with patient advocacy groups for research and outreach.
Citizen Science: Participate in data collection and analysis projects to support rare disease research.
Ethical Considerations: Discuss the balance between investment in rare disease research and broader public health needs.

Aspect	Common Diseases	Rare Diseases
Prevalence	High	Low
Diagnosis	Standardized	Challenging, delayed
Research Funding	Substantial	Limited
Treatment Availability	Widespread	Often scarce or experimental
Social Impact	Well-understood	Often misunderstood, isolating

Kaplan, F.S., et al. (2021). “Fibrodysplasia Ossificans Progressiva.” Nature Reviews Disease Primers, 7, 65.
Topol, E.J. (2020). “High-performance medicine: the convergence of human and artificial intelligence.” Nature Medicine, 25, 44–56.
U.S. Food & Drug Administration. “FDA Approves Innovative Gene Therapy for SMA.” 2022.

Rare diseases are diverse, challenging, and collectively significant.
Emerging technologies are transforming diagnosis and treatment.
Misconceptions hinder progress—education is essential.
Science club members can make a difference through outreach, research, and advocacy.