Stüve-Wiedemann Syndrome

Stüve-Wiedemann syndrome (SWS) is a rare autosomal recessive congenital primary skeletal dysplasia, characterized by small stature, bowing of the long bones, camptodactyly, hyperthermic episodes, respiratory distress/apneic episodes and feeding difficulties that usually lead to early mortality.

Epidemiology

SWS is a rare syndrome with few cases reported to date, but the disease is relatively common in the United Arab Emirates, apparently due to a high number of consanguineous unions, with a reported prevalence of approximately 0,5/10,000 births.

Clinical description

SWS is characterized by short stature, bowing of extremities that affect the lower limbs more than the upper limbs, camptodactyly, respiratory distress/apneic spells and hyperthermic episodes frequently associated with feeding/swallowing difficulties. Other clinical findings are mask-like face, pursed mouth, hypoplastic midface, osteopenia, congenital contractures and muscular hypotonia. The condition is fatal in most cases as a result of respiratory distress or hyperthermia. However, survival beyond one year have been reported in few cases, and patients develop severe spinal deformities, along with streaky osteoporosis and spontaneous fractures, bowing of the lower limbs (with prominent joints) and dysautonomia (including temperature instability, absent corneal and patellar reflexes, and smooth tongue). Motor development is generally delayed but no intellectual deficit has been reported.

Etiology

SWS is due to missense or nonsense mutations in the leukemia inhibitory factor receptor (LIFR) gene (5p13.1). These null mutations lead to modifications in the stability of the LIFR transcripts, inhibiting synthesis of the LIFR protein and resulting in alterations in the JAK/STAT3 signaling pathway. In some patients diagnosed for SWS, LIFR mutations were not identified, suggesting that other genes may be involved in the disease.

Diagnostic methods

The diagnosis of SWS is mainly postnatal, based on clinical and radiological findings. Radiographic examination reveals bowed long bones with cortical thickening and rarefaction, wide metaphysis with decreased density and blurred margins, and abnormal trabecular pattern. Other features include flared iliac wings, hypoplasia of the lower ilia. Genetic molecular testing for LIFR mutation may be useful to confirm SWS diagnosis.

Differential diagnosis

Differential diagnosis includes Crisponi syndrome (cold-induced sweating syndrome) and other skeletal dysplasias, such as Ehlers-Danlos syndrome type IX, Campomelic dysplasia and autosomal dominant Larsen syndrome (see these terms).

Antenatal diagnosis

In some cases, ultrasound examination may be useful to predict the presence of SWS before birth. Prenatal symptoms can sometimes be seen in the late second- or third trimester and include oligohydramnios, intrauterine growth restriction despite normal Doppler findings about the umbilical artery, camptodactyly, bowing of the lower bones affecting the tibia more than the femur, and micromelia.

Genetic counseling

SWS is a congenital condition inherited as an autosomal recessive disorder.

Management and treatment

To date, SWS management is only symptomatic and should include prevention of lung aspirations and chocking while eating (intubation, nasogastric tube feeding and/or gastrostomy often required during the first year of life), physiotherapy and/or surgery for bone malformations, eyes protection from damage to prevent visual loss, and osteopenia or osteoporosis treatment. Predisposition to hyperthermia necessitates caution during procedures requiring anesthesia.

Prognosis

SWS is a life-threatening disease which is usually fatal during the neonatal period, due to respiratory distress or hyperthermic episode. However, more patients are surviving for longer (into and, in some cases, beyond adolescence), if diagnosed and monitored appropriately.