"Gibbus or 'hump" (details from "Dwarf or Gnome missing one foot ") (see related A) Mirabell gardens - Zwerglgarten (Dwarf garden) , Salzburgh, Austria

In medical parlance, illustrated here is a scoliosis due to defects of the thoraco-lumbar vertebra resulting in a kyphosis - such is observed in individuals with achondroplasia, neurofibromatosis type 1 (NF-1), cretinism (congenital hypothyroidism), and storage diseases, in particular, mucopolysaccharidoses (MPS). In this series, achondroplasia combined with NF-1 is illustrated. 

Statistically, concurrence of two mutations (NF-1) and achondroplasia, even if as frequent as 1 x 1000 would render the concurrence as unlikely as 1 per 1000000.