Genetics of patella hypoplasia/agenesis

Clin Genet. 2018 Jul;94(1):43-53. doi: 10.1111/cge.13209. Epub 2018 Apr 11.


The patella is a sesamoid bone, crucial for knee stability. When absent or hypoplastic, recurrent knee subluxations, patellofemoral dysfunction and early gonarthrosis may occur. Patella hypoplasia/agenesis may be isolated or observed in syndromic conditions, either as the main clinical feature (Nail-patella syndrome, small patella syndrome), as a clue feature which can help diagnosis assessment, or as a background feature that may be disregarded. Even in the latter, the identification of patella anomalies is important for an appropriate patient management. We review the clinical characteristics of these rare diseases, provide guidance to facilitate the diagnosis and discuss how the genes involved could affect patella development.

Keywords: TBX4; limb development; patella agenesis; patella hypoplasia.

Publication types

  • Review

MeSH terms

  • Alleles
  • Bone Diseases, Developmental / diagnosis
  • Bone Diseases, Developmental / genetics
  • Diagnosis, Differential
  • Genetic Association Studies* / methods
  • Genetic Predisposition to Disease*
  • Hip / abnormalities
  • Humans
  • Ischium / abnormalities
  • Multimodal Imaging / methods
  • Musculoskeletal Abnormalities / diagnosis*
  • Musculoskeletal Abnormalities / genetics*
  • Patella / abnormalities*
  • Patella / diagnostic imaging
  • Phenotype
  • Syndrome

Supplementary concepts

  • Absent patella
  • Ischiopatellar dysplasia