Genetic / Eponymous Conditions Flashcards
Charcot Marie Tooth key points
Hereditary sensory-motor Neuropathy
Autosomal Dominant most common (variable penetrance)
7 types (type 1 and 2 most common)
Type 1 = Demyelination (motor > sensory)
Type 2 = Wallerian degeneration (motor = sensory)
Peroneus Brevis / Tibialis Anterior and Intrinsics of foot and hand most commonly involved
Cavus feet / Hammer toes / Hip dysplasia / Scoliosis
Duchenne Muscular Dystrophy key points
X-linked recessive Absent dystrophin protein Fibro-fatty muscle infiltration due to abnormal repair Calf pseudohypertrophy Scoliosis Cardiomyopathy Joint contractures Elevated CPK (due to leaky membranes) Gower's sign Treat with steroids Early scoliosis correction (before 40 degrees and before FVC reduced 35%) Can do joint contracture releases
FacioScapuloHumeral Dystrophy key points
Autosomal Dominant Normal life expectancy Scoliosis and "Bent spine" (camptocormia) Transverse smile Shoulder girdle wasting Surgical mgmt: Scaphulothoracic fusion
Marfans features
Cardiac root dilatation Arachnodactyly Thumb sign (tip of the thumb protrudes from palm) Superior lens dislocation Protrusio acetabuli Arm span > height Wrist sign (thumb and little finger overlap around wrist) Scoliosis Planovalgus feet Pectus excavatum Hyperlaxity
Neurofibromatosis 1 diagnostic criteria
Cafe-au-lait spots (6 or more) Axillary freckling (or inguinal) Fibromas (One Plexiform or Two Neurofibromas) Eye Hamartomas (Lisch nodules) Skeletal dysplasias (Anterolateral tibial bowing) Positive Family History Ocular (Optic nerve glioma) Tumor (Optic nerve glioma)
CAFE SPOT
Autosomal Dominant
NF1 mutation on chromosome 17q21 (neurofibromin protein)
Friedrich’s Ataxia key points
Autosomal recessive
Lack of frataxin (mitochondreal protein in iron metabolism and oxidative stress)
Cavovarus foot / Scoliosis
Cardiomyopathy (usual cause of death)
Classic triad: ataxia / areflexia / positive plantars
Cavus deformity does not respond to non-op
Spinal Muscular Atrophy key points
Autosomal recessive
Weakness starts proximal and moves distal
Hip dislocation / scoliosis / contractures
Non-op hips
Always surgery for scoliosis
(Flat feet and absent deep tendon reflexes as opposed to Duchene’s who are toe walkers and have normal reflexes)
Gaucher’s disease
Autosomal recessive
Genetic condition of GlucoCerebroSide (a lipid) accumulation in organs (white cells and macrophages).
GlucoCerebroSidase enzyme deficiency
Lysosomal storage disease
Ortho: Fractures Osteomyelitis Joint contractures Bone crisis (osteonecrosis) Erlenmeyer flask distal femur Physeal problems (Reserve Zone)
Non-ortho: Anaemia Thrombocytopaenia Infection CNS involvement (seizures, develop delay)
Treated with enzyme replacement - must be done pre-op
Meyer dysplasia
A fragmentation and reossification of the femoral epiphysis. Occurs in 2-3 year olds (younger than LCP), asymptomatic, requires no treatment. Often considered a normal variation.
Neurofibromatosis 1 Skeletal manifestations
SHAFT Scoliosis Hemihypertrophy Atlantoaxial instability Forearm pseudarthrosis Tibia pseudarthrosis
Anterolateral bowing / pseudarthrosis of the tibia Pseudarthrosis of the forearm Hemihypertrophy Scoliosis Kyphosis Atlantoaxial instability
Charcot-Marie Tooth Skeletal manifestations
CASH: CavoVarus / Claw toes Atrophy (intrinsics of hand, Tibialis Anterior) Scoliosis Hip Dysplasia
Pes CavoVarus Hammer / Claw toes Hip dysplasia Scoliosis Atrophy of intrinsic hand muscles Dropfoot (TibAnt weakness)
Friedreich’s ataxia key points
Autosomal recessive Frataxin defect (mitochondrial protein), ch 9q13
Scoliosis Ataxia Areflexia Babinski positive Cavovarus foot Cardiomyopathy
Marfan Syndrome
Autosomal Dominant
Fibrillin 1 gene mutation on Ch15q21
Cardiac
Ocular
Ortho
Face:
Superior lens dislocation
High arched palate
Chest: Pectus excavatum / carinatum Spontaneous pneumo Aortic root dilatation / dissection Mitral valve prolapse
Spine:
Scoliosis
Dural ectasia
Meningocele
Limbs: Arachnodactyly DolichoStenoMelia Laxity Dislocations Planovalgus Protrusio
Diastrophic Dysplasia
Autosomal Recessive
Sulfate transporter protein mutation (DTDST gene, chr5)
Rhizomelic dwarfism Cleft palate Cauliflower ears Hitchhiker's thumb Thoracolumbar scoliosis Cervical kyphosis - often resolves spontaneously Genu valgum Rigid clubfeet Skewfoot Hip and knee contractures
Osteogenesis Imperfecta
Autosomal Dominant (mild I and IV)
Autosomal Recessive (severe II and III)
Decreased amount of Normal Type I collaged
COL 1A1 and COL 1A2 mutations (abnormal collaged cross-linking)
Bones heal normally, but don’t remodel
Bone fragility Ligamentous laxity Short stature Scoliosis Codfish vertebrae (from compression fractures) Basilar invagination Olecranon apophysis avulsion fractures Coxa vara Congenital antero-lateral radial head dislocation
Blue sclerae Hearing loss Triangle face Dentogenesis imperfecta Wormian bones Malignant hyperthermia Mitral valve prolapse, Aortic regurgitation
