SNP Shot: Genomic Insights

Inclusion body myopathy with early-onset Paget disease and frontotemporal dementia (IBMPFD) is a rare disease impacting the muscles, skeleton, and brain.

Muscle weakness (myopathy) is often the initial symptom of IBMPFD, typically appearing in middle age. This weakness primarily affects the hip and shoulder muscles, resulting in difficulty with activities like climbing stairs or raising arms. The weakness progresses to other muscles in the limbs. In some cases, the respiratory and cardiac muscles are affected, potentially leading to life-threatening breathing problems and heart failure.

Approximately 50% of individuals with IBMPFD develop Paget disease of bone, which causes abnormal bone growth, leading to larger and weaker bones. This primarily affects the hip, spine, skull, and long bones of the arms and legs. The main symptom of Paget disease is bone pain, particularly in the hips and spine. Complications depend on the affected bones. In rare instances, the bones become so weak they are prone to fractures.

Around one-third of IBMPFD patients experience frontotemporal dementia, a brain disorder typically emerging in their forties or fifties. Early symptoms include difficulty with speech, remembering words and names (dysnomia), and using numbers (dyscalculia). Over time, the condition damages brain areas controlling reasoning, personality, social skills, speech, and language. Personality changes, impaired judgment, and inappropriate social behavior are characteristic features. As the dementia progresses, affected individuals eventually lose the ability to speak, read, and perform self-care tasks.

Less common features of IBMPFD include amyotrophic lateral sclerosis (ALS), a severe muscular disease, and progressive movement and balance problems resembling Parkinson's disease.

The life expectancy for individuals with IBMPFD is typically into their fifties or sixties.

Inheritance:

IBMPFD follows an autosomal dominant inheritance pattern, meaning only one copy of the mutated gene is needed to cause the condition. Most individuals inherit the mutated gene from a parent who also has the condition.