FFU complex: an analysis of 491 cases

Abstract

A study of 491 patients with femur-fibula-ulna (FFU) complex is presented. The term FFU complex has been proposed for cases in which the femur, fibula and/or ulna show defects, which tend to be associated. These cases are usually sporadic. Some rare anomalies of the arms which are present are particularly frequent in FFU complex. These are amelia, peromelia of humerus, humero-radial synostosis and defect of ulna. In our study, 491 patients were investigated for involvement of limb malformations. Our results, showing nearly equal proportions of the most common malformations in four analysed groups (with one, two, three and four limbs affected) supports the hypothesis that even if one arm or one leg only is affected, the cases may still be classifiable as FFU complex. There is a striking asymmetry in presence and in degree. All malformations are more often unilateral than bilateral. Upper limbs are affected more often than lower limbs. The right side and the male sex are preferentially affected. The limb malformations present in the FFU complex are different from those seen in most other types of limb defects, so there is virtually no overlap between FFU and other limb malformations. Some arguments in favour of early somatic mutation as a cause are discussed.

Lower limb deficient children in the Netherlands

“…None of these had chromosomal defects. Two (2) of these 23 however, were registered with FFU complex (Lenz, et al, 1993), 1 with possible FFU complex, 1 with amniotic bands syndrome and 1 with oromandibular/limb hypogenesis.…”

Prenatal Ultrasound Diagnosis of a Femur-Fibula-Ulna Complex during the First Half of Pregnancy

“…In an analysis of 491 cases of FFU complex, the most common malformations of the upper limbs were amelia, peromelia and ulna defects, and the most common malformations of the lower limbs were amelia, femur defects and fibula defects [3]. The precise determination of a FFU complex is particularly difficult because cases which belong to this complex can vary widely from one another.…”

“…The degree of asymmetry, the sporadic occurrence, no transmission from parent to child, no paternal age effect, no increased rate of consanguinity among the parents and discordance in monozygotic twins preclude any simple genetic explanation. There is no evidence of an environmental cause either [3].…”

“…The presence and degree of the symptoms of the FFU complex are of remarkable asymmetry, occurrence being unilateral more often than bilateral, with preference of the right side and upper limbs and mainly male fetuses being affected [2,3].…”

Aqueiropodia: primer reporte de caso en Argentina

“…9 El cuadro de fémur-peroné-cúbito (FemurFibula-Ulna; FFU, por sus siglas en inglés) es una entidad que ocurre en forma esporádica y que se caracteriza por defectos de reducción que suelen afectar al fémur, al peroné y/o al cúbito, pero de manera muy variable y en forma asimétrica. 10 El síndrome de Roberts se caracteriza por un defecto de reducción de los miembros frecuentemente mesomélico, fisuras orales, microcefalia, anomalías oculares (cataratas u opacidad corneal), ciertas dismorfias faciales y déficit intelectual grave, entre otras anomalías. El patrón de herencia es autosómico recesivo.…”