IHH and acrocapitofemoral dysplasia: [6] Intriguingly, some of the growth abnormalities observed, particularly in Patients 1 and 3 (Figure 2), are also akin to those in patients born with IHH deficiency, which causes the autosomal recessive syndrome acrocapitofemoral dysplasia that is characterized by short-limb dwarfism and brachydactyly.