Clinical History:
- Chief complaint: Weakness first presenting in teens.
- Family history: Brother with myopathy.
- Medication: Denies statins.
- Physical exam: Moderate forearm atrophy; moderate distal weakness; sensation intact; reflexes 1+ throughout, plantar flexor; coordination normal; gait normal.
- Lab results: Highest CK 198, myositis antibody panel negative.
What is the diagnosis based on the reference images below?
Answer:
Hereditary inclusion body myopathy
HIBM – group of uncommon muscle wasting disorders.
- Also described as distal myopathy with rimmed vacuoles.
- Quadriceps are relatively spared.
- Histology – chronic necrotizing myopathy/dystrophy; usually with many inclusion bodies. May have little to no inflammation.
- Genetics – multiple genes identified.
- GNE mutations are most common cause, usually Jews of Persian descent.
- MYHC2A – less common mild form.
- VCP, HNRPA2B1 or HNRNPA1 – Multisystem proteinopathy. Associated with early onset Paget’s disease and frontotemporal dementia.
Reference(s) / Additional Reading:
- Broccolini A, Mirabella M. Hereditary inclusion-body myopathies. Biochim Biophys Acta. 2015 Apr;1852(4):644-50.
Quick note: This post is to be used for informational purposes only and does not constitute medical or health advice. Each person should consult their own doctor with respect to matters referenced. Arkana Laboratories assumes no liability for actions taken in reliance upon the information contained herein.
