[MIM 147 891]

(Ischiopatellar dysplasia, small patella syndrome)

Incidence: < 1/106. Autosomal dominant transmission of a mutation of the TBX4 gene (17q23.2).

Association of:

-        aplasia or hypoplasia of the patella,

-        absence, delay or irregularity of ossification of ischiopubic branches and/or infra-acetabular incisures

-        and, in the majority of patients: abnormalities of the femur and foot (wide space between the first and second toes, short fourth and fifth rays of the foot, flat foot).

Craniofacial abnormalities (micrognathia, cleft palate, flat nose and prominent forehead) have been reported in a few cases.

The clinical symptomatology is very variable: asymptomatic, recurrent luxations starting from childhood, inability to run or ride a bicycle, gonarthrosis in the elderly.

Anesthetic implications:

risk of difficult intubation in case of craniofacial abnormalities

References : 

-        Haarman MG, Kerstjens-Frederikse WS, Berger RMF.
The ever-expanding phenotypical spectrum of human TBX4 mutations: from toe to lung.
Eur Respir J 2019; 54: 1901504

Updated: October 2021