Definition: Nager syndrome consist of limb anomalies including absence of the radius, synostosis of the radius and ulna, hypoplasia or absence of the thumbs as well as severe micrognathia and malar hypoplasia[1],[2].

Synonyms: Mandibulofacial dysostosis, Treacher Collins type, with limb anomalies; Nager acrofacial dysostosis. Rodriguez lethal Acrofacial Dysostosis syndrome is a variant with preaxial limb deficiencies,  postaxial limb anomalies, severe hypoplasia of the shoulder and pelvic girdles, and cardiac and CNS malformations[3].

Incidence: uncommon.

Etiology: Nager may represent new mutations of an autosomal dominant trait.

Diagnosis: Severe micrognathia and the typical micromesomelia with the abnormal hand mainly suggest the diagnosis. Accessory anomalies have frequently been reported.

Genetic anomalies: Nager syndrome is on chromosome 9 (q32)[4].

Differential diagnosis: Other disorders with micrognathia and distal ectromelia such as trisomy 18.

Prognosis: Lethal from lung hypoplasia due to severe mandibular hypoplasia.

Management: Termination of pregnancy can be offered before viability. Standard prenatal care is not altered when continuation the pregnancy is opted for. Confirmation of diagnosis after birth is important for genetic counseling.

Reference:

[1] Slingenberg, B. : Misbildungen von Extremitaeten. Virchows Arch. Path. Anat. 193: 1-92, 1908.

[2] Nager, F. R., de Reynier, J. P. : Das Gehoerorgan bei den angeborenen Kopfmissbildungen. Pract. Otorhinolaryng. 10 (suppl. 2): 1-128, 1948.

[3] Rodriguez, J. I., Palacios, J., Urioste, M. : New acrofacial dysostosis syndrome in 3 sibs. Am. J. Med. Genet. 35: 484-489, 1990.

[4] Zori, R. T., Gray, B. A., Bent-Williams, A., Driscoll, D. J., Williams, C. A., Zackowski, J. L. : Preaxial acrofacial dysostosis (Nager syndrome) associated with an inherited and apparently balanced X;9 translocation: prenatal and postnatal late replication studies. Am. J. Med. Genet. 46: 379-383, 1993.