EP10.05: Firs trimester diagnosis of bilateral fibular aplasia, tibial campomelia and pligosyndactyly (FACTO) syndrome: a case report

A 34 year old Caucasian p atient, para 1, was referred to our maternal fetal medicine unit at 12 weeks and 5 days, for suspected fetal structural abnormality affecting lower limbs. An accurate fetal scan w as performed, showing a single fetus with crown-rump length normal for dates. Nuchal translucency was within normal ranges. The examination of lower limbs showed, for both sides, absence of the fibula, tibial campomelia, talipes valgus, short femur and oligosyndactyly. In addition, examination of upper limbs showed oligosyndactyly involving both hands. Prenatal invasive testing was offered and the patient refused. The ultrasound findings were suggestive of a fibular aplasia, tibial Campomelia and oligosyndactyly (FACTO) syndrome. After genetic and orthopedic counselling about treatment options, prognosis and possible management, the couple opted for termination of pregnancy at 15 weeks of gestation. Postnatal evaluation confirmed the prenatal findings and diagnosis. Fibular hemimelia-aplasia is a rare abnormality, with estimated incidence of less than 1 per 50000 births. The exact etiology is still unclear. Generally the defect is unilateral, more commonly on the right side. The short/absent fibula can affect the normal development of the tibia, resulting in associated bowing and angulation of the latter (tibial campomelia). The position of the ankle can also be affected, resulting in talipes valgus, as in our case. A typical association is with tarsal anomalies, including agenesis or hypoplasia. The ipsilateral foot usually lacks of lateral rays, resulting in oligosyndactyly. This condition has usually been reported as unilateral, involving just one of the lower limbs. In conclusion we report the very rare occurrence of fibular aplasia involving both limbs, showing all the abnormalities peculiar of the FACTO syndrome, diagnosed in the first trimester of pregnancy.