Skeletal dysplasia

Question 1

Thanatophoric dysplasia

Answer 1

LETHAL
micromelia, rhizomelia (shortening of proximal limbs), normal trunk length with narrow thorax, large head with prominent forehead. Telephone receiver femurs, cloverleaf skull. Autosomal dominant in FGFR3. Lethal.

Question 2

Hypophosphatemia

Answer 2

Skeletal demineralization & shortening & bowing of tubular bones. Caused by mutations in ALPliver gene. Perinatal lethal form will have micromelia.

Question 3

Achondroplasia

Answer 3

Achondroplasia – Most common non-lethal skeletal dysplasia. Autosomal dominant, complete penetrance. Rhizomelic shortening of limbs, macrocephaly. Most long bone growth abnromality not recognized until 3rd trimester. Mutation in FGFR3.