Genitopatellar syndrome


Disease Overview

Genitopatellar syndome (GPS) is a genetic condition which affects different parts of the body. The most common signs and symptoms (features) of GPS include abnormal genitals (for boys, undescended testicles and underdeveloped scrotum; for girls, small labia and large clitoris), missing or underdeveloped kneecaps (patellae), stiff large joints with limited movement (such as contractures of hips and knees or clubfoot), developmental delay, and intellectual disabilities. Other features may include missing the structure that connects the two sides of the brain (agenesis of the corpus callosum), swelling of the kidney due to build up of urine (hydronephrosis) and congenital heart defects (the baby’s heart did not form normally). Thyroid problems have been reported in some cases.[12901][12902]

Genitopatellar syndrome (GPS) is caused by changes or mutations in the KAT6B gene..[12901][12902][12903] Diagnosis of GPS is usually suspected by the signs and symptoms (features) seen in the child. It is confirmed by genetic testing. There is no cure for GPS. Treatment focuses on the features present in each child and may include surgery (for example to correct heart defects or clubfoot), speech therapy, physical therapy (to increase range of motion of joints), and early childhood intervention and special education programs (for developmental delays and intellectual disability).[12903]

As of 2016, medical researchers are trying to decide if genitopatellar syndrome (GPS) is a separate syndrome from Say–Barber–Biesecker–Young–Simpson syndrome (SBBYSS). Both syndromes are caused by changes (mutations) in the same gene (KAT6B). The two syndromes also share a lot of the same features, and some children with mutations in KAT6B gene have a combination of features that fall in between the GPS and SBBYSS. This suggests that GPS and SBBYSS may be two ends of a spectrum of the same syndrome..[12901][12902]


  • Absent patellae, scrotal hypoplasia, renal anomalies, facial dysmorphism, and mental retardation
  • Absent patellae-scrotal hypoplasia-renal anomalies-facial dysmorphism-intellectual disability syndrome

For more information, visit GARD.

National Organization for Rare Disorders