245. Inherited C.T. Disorders Flashcards

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1
Q

How are children Xrays different?

A
  1. Cartilage precursors of bone not mineralized = not visible
  2. Growth plate radiolucent until growth ceases
  3. Epiphysis lucent (dark), mineralizing at predictable times during childhood/adolescence

Good to compare bone age to chronological age

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2
Q

Achondroplasia

Type, Sx, Imaging

A

Metaphyseal Dysplasia
Most common cause of dwarphism
Shortening of proximal limbs, trident hand, macrocephaly, kyphosis, cor pulmonale (RV problems), apnea, normal intelligence

Pelvis: horizontal acetabular roof “paddle w/o handle”
Vertebrae: distance b/w pedicles decreases down spine
Abnormally long fibula

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3
Q

Genetics of Achondroplasia (Pathophysiology, possible tx)

A
AD inheritance/de novo (more likely in older fathers)
Mutated FGFR3 (Gly380Arg) = constitutively active = always inhibits chondrocyte proliferation in zone of hypertrophy

CNP analoge - binds NPR-B = could inhibit FGF as possible tx

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4
Q
Osteogenesis Imperfecta
(type, genetics, sx, tx)
A

Metaphyseal Dysplasia (brittle bone disease)
Abnormal type 1 collaged
AD - haploinsufficiency/dominant negative
Wide rande of severity - fractures with minimal trauma, blue sclera, “wormian” islands bones of skull
Tx: bisphosphonates: harden bone

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5
Q

Ehlers-Danlos Syndrome

type, genetics, sx

A

Collagenopathy - Type V collagen defect
Soft, velvety skin - hyperelastic/fragile - easy to tear/bruise
Joint hypermobility, dislocations
MV prolapse, hiatal hernia, anal prolapse, flat feet

Genetics: mutation in COL5A1/2 = null allele (AD)

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6
Q

Marfan Syndrome

Pathophysiology, Genetics

A

AD, 30% de novo
Fibrillin 1: forms microfibrils as scaffold for elastic fiber formation and bind TGF B

Defect in fibrillin: problem with elastic tissue and TGF B released in excess

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7
Q

Marfan Syndrome Sx

A
Scoiliosis, Arachnodactyly, Joint Laxity, Ocular Abnormalities (Myopia)
CV Disease (MV Prolapse, Aortic root dilation, dissection, aneurysm)
Pts are long, lean, long limbs, sternum abnormality
Flat feet, +thumb-and-wrist sign
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