NM Conditions Flashcards
Autosomal Recessive
Mutation in the GAN gene that encodes for Gigaxonin (involved in cross-linking of intermediate filaments)
Path: Large focal AXONAL swelling that tightly packed disorganized neurofilaments
Giant Axonal Neuropathy
Sensorimotor neuropathy with corticospinal involvement + UMN signs
Optic atrophy => Vision loss
Hallmarks: Walking on the inner edges of the feet, tightly curled hair
Giant Axonal Neuropathy
Autosomal Dominant
Peroxismal disorder that results from a defect in an enzyme involved in fatty acid metabolism, leading to accumulation of Phytanic Acid.
Refsum’s Disease
Retinitis Pigmentosa (Night blindness, visual field constriction)
Cardiomyopathy
Skin changes
Neuropathy: Large sensorimotor neuropathy
Hearing Loss
Anosmia, Ataxia, Cerebellar signs
Refsum Disease
Mutation in Thymidine Phosphorylase Gene
Retinitis Pigmentosa, Demyelinating neuropathy
Intestinal Pseudoobstruction
Ophthalmoparesis
Myoneurogastrointestinal Encephalopathy (MNGIE)
Autosomal Recessive
Defective triglyceride transport => Abnormal low-density lipoprotein secretion
Fat malabsorption results in vitamin deficiencies
DX: Low levels of serum beta lipoprotein & vitamin E + Peripheral smear showing acanthocytes
Abetalipoproteinemia
Bassen-Kornzweig Syndrome
Autosomal Dominant
Mutation in Transthyretin (plasma protein that transports thyroxine & other proteins)
Presents in the 3rd/4th decade of life
Both small and large nerve fibers are affected
Pronounced loss of pain and temperature sensation - sparing posterior columns
Lancinating pains and dysesthesias, Autonomic dysfunction.
Nerve/Rectal/Fat pad biopsy will show congo red staining & apple-green birefringence on polarized light
Familial Amyloid Polyneuropathy 1
Autosomal Dominant
4th/5th decade of life
Carpal Tunnel Syndrome, Slow progressive polyneuropathy - NO AUTONOMIC FEATURES
Familial Amyloid Neuropathy 2
Autosomal Dominant: Duplication of PMP22
First two decades of life
Progressive weakness, Muscle atrophy, Kyphosis, sensory loss
Hammer toes, high arched feet, Palpably enlarged nerves due to peripheral nerve hypertrophy, Pes cavus
CMT1A
Autosomal Dominant
Mutation in the Myelin Protein 0
CMT1B
X-linked
Mutation in Connexin 32 gene
Males more severely affected
CMTX
Autosomal Dominant
Optic Atrophy
CMT2A2
Foot ulcerations
CMT2B
Vocal cord paralysis, Intercostal + Diaphragmatic weakness
CMT2C
Presents in infancy
Proximal weakness, Absent DTRs, Hypertrophy of peripheral nerves, Prominent sensory symptoms
CMT3
Dejerine-Sottas Syndrome
Hypertrophic Neuropathy of Infancy
