Femoral-facial syndrome (FFS), also known as femoral hypoplasia-unusual facies syndrome (FHUFS), is a rare and sporadic multiple congenital anomaly syndrome comprising bilateral femoral hypoplasia and characteristic facial features, such as long philtrum, thin upper lip, micrognathia with or without cleft palate, upward-slanting palpebral fissures, and a short nose with broad tip. Other features, such as renal anomalies, are more variable (summary by Nowaczyk et al., 2010).

The Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome (AARRS) is a rare autosomal recessive disorder characterized by severe malformations of upper and lower limbs with severely hypoplastic pelvis and abnormal genitalia. The disorder is believed to represent a defect of dorsoventral patterning and outgrowth of limbs (summary by Kantaputra et al., 2010). Overlapping limb reduction syndromes, less severe in nature, that are also caused by homozygous mutation in the WNT7A gene include Fuhrmann syndrome (228930), characterized by fibular aplasia or hypoplasia, femoral bowing, and poly-, syn-, and oligodactyly, and Santos syndrome (228930), characterized by fibular agenesis/hypoplasia, oligodactylous clubfeet, and anonychia/nail hypoplasia. Al-Qattan et al. (2013) stated that AARRS and Fuhrmann syndrome can be differentiated by the following features, which are seen only in AARRS: complete aplasia of 1 or both lower limbs, and absent elbow with radiohumeral synostosis. In addition, the number of digits per hand is 1 to 3 in AARRS, whereas there are 4 to 5 digits in Fuhrmann syndrome. 'Phocomelia' refers to an intercalary limb defect with the hand or foot being directly attached to the humerus or femur (absent zeugopod) or directly attached to the trunk (absent stylopod and zeugopod). AlQattan et al. (2013) stated that the limb defect observed in Schinzel phocomelia syndrome represents 'true' phocomelia, whereas the limb defect in AARRS is an 'apparent' phocomelia, in which there is absent ulna with radiohumeral synostosis. The authors described 3 radiologic features that define 'apparent' phocomelia: a single arm/forearm bone that appears too long to be the humerus alone; a thicker cortex at the area of the radiohumeral synostosis, with or without slight angulation at the site of synostosis; and the apparently single bone resembling the humerus proximally and the radius distally. The authors also noted that phocomelia is not a feature of the allelic disorder Fuhrmann syndrome (228930). Other distinguishing features of Schinzel phocomelia syndrome include normal nails and dorsal hand skin; distoproximal gradient of lower limb defects, without a resultant stick-like appearance; and a characteristic large cranial defect. AlQattan et al. (2013) concluded that Schinzel phocomelia syndrome and AARRS are distinct phenotypes.

Fuhrmann syndrome is an autosomal recessive limb reduction disorder characterized by severe bowing of the femora and aplasia or hypoplasia of the fibulae and ulnae. The radius may be shortened and bowed. Patients also exhibit variable poly- and/or oligodactyly, including absence or coalescence of tarsal bones, absence of various metatarsals, hypoplasia and aplasia of toes, clinodactyly, hypoplasia of fingers and fingernails, and postaxial polydactyly. Hypoplasia of the pelvis and congenital dislocation of the hip have also been observed (Fuhrmann et al., 1980; Pfeiffer et al., 1988). Overlapping limb reduction syndromes that are also caused by homozygous mutation in the WNT7A gene include Al-Awadi/Raas-Rothschild syndrome (AARRS; 276820), consisting of absence of ulna and fibula with severe limb deficiency, and Santos syndrome (228930), consisting of fibular agenesis/hypoplasia, oligodactylous clubfeet, and anonychia/nail hypoplasia. Al-Qattan et al. (2013) stated that AARRS and Fuhrmann syndrome can be differentiated by the following features, which are seen only in AARRS: complete aplasia of 1 or both lower limbs, and absent elbow with radiohumeral synostosis. In addition, the number of digits per hand is 1 to 3 in AARRS, whereas there are 4 to 5 digits in Fuhrmann syndrome. AlQattan et al. (2013) also noted that phocomelia is not a feature of Fuhrmann syndrome.