Weismann-Netter Syndrome

Description

The diagnostic hallmarks of Weismann-Netter syndrome (WNS) are anterior bowing of the diaphyses of the tibia and fibula, broadening or 'tibialization' of the fibula, posterior cortical thickening of both bones, and short stature. The diaphyses of other long bones may be similarly affected, but usually to a milder degree. Some WNS patients have also displayed mental retardation (summary by Peippo et al., 2009).

Clinical Features

Weismann-Netter and Stuhl (1954) reported an apparently familial disorder of anterior bowing of tibiae and fibulae, with cortical hyperostosis on the concave side of the curvature. Associated anomalies were short stature and, in some cases, mental retardation. Familial incidence was noted by Larcan et al. (1963). Hoefnagel (1969) and Keats and Alavi (1970) reported cases in the U.S.

Amendola et al. (1980) reported 3 unrelated patients and reviewed 37 previously reported patients. They noted that the changes in the legs resemble 'saber shins' of congenital syphilis. Diaphyseal bowing occurs in other long bones, suggesting that this is a form of diaphyseal dysplasia. 'Squaring' of the iliac bones is also a feature. Mental retardation, goiter, and anemia, previously noted associations, are probably only coincidental. Patients are short (adult height, 47 to 61 inches).

Robinow and Johnson (1988) reported a patient who showed anterior bowing of the tibias and lateral bowing of the femurs. The patient, his mother, and several maternally related males had X-linked ichthyosis. Serum calcium phosphorus, alkaline phosphatase, and vitamin D metabolite levels were normal.

Bryke et al. (1990) described 3 unrelated children with WNS.

Francis et al. (1991) reported a 4-year-old boy with WNS. In addition to the classic findings, they described bilateral epicanthal folds, multiple caries of the primary teeth, which were otherwise well formed, and an extra flexion crease of the right fifth finger.

Tieder et al. (1995) reported a 5-year-old girl with WNS in whom lower limb deformities, delayed ambulation, short stature, facial dysmorphism, and scoliosis were demonstrated.

Caksen and Kurtoglu (2004) reported a 2-year-old girl with typical findings of Weismann-Netter syndrome who was misdiagnosed as having rickets.

Peippo et al. (2009) reported a 23-year-old man who was first seen at 13 years of age and was noted to have short stature, severe genu valgum, anterior bowing of both lower legs, and pronounced lumbar lordosis. X-ray examination showed findings characteristic of WNS, including the mild diaphyseal changes in other long bones, forward tilt of the sacrum, and pronounced lordosis that are typical. The patient also had slightly misshapen first metacarpal and metatarsal bones, not previously described in WNS. He was born of healthy parents and had 11 healthy sibs. He only started school after immigrating to Finland at 11 years of age, and at age 23, had not learned to read or write and displayed mild to moderate mental retardation on neuropsychologic testing. Peippo et al. (2009) reviewed the more than 100 reported cases of WNS and noted that the condition is experienced by patients as relatively harmless, with no effect on ambulation; usually it is an incidental finding in adult patients seeking medical help for unrelated medical issues.

Inheritance

According to Amendola et al. (1980), family history has been documented in 14 instances, including mother and 3 children (Weismann-Netter and Stuhl, 1954); sibs and identical twins (Krewer, 1961) and 5 females in 3 generations of a family (Breuzard et al., 1960). There is, however, no gender predominance in the 40 reported cases (23 male, 17 female).

Based on a review of the 100 reported cases of WNS, Peippo et al. (2009) stated that the frequent familial cases suggest a genetic defect with autosomal dominant inheritance.