hereditary neuralgic amyotrophy

Definition: Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant form of recurrent focal neuropathy characterized clinically by acute, recurrent episodes of brachial plexus neuropathy with muscle weakness and atrophy preceded by severe pain in the affected arm. Hereditary neuralgic amyotrophy can be caused by mutations in the SEPT9 gene (604061).

Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant recurrent neuropathy affecting the brachial plexus. HNA is triggered by environmental factors such as infection or parturition. HNA is the first monogenetic disease caused by mutations in a gene of the septin family (SEPTs).

HNA is a rare, inherited form of brachial neuritis whose phenotypic spectrum may include hypotelorism, cleft palate and other minor dysmorphisms.

HNA maps to chromosome 17q25 and is associated with mutations in the SEPT9 gene.

Synopsis

 facial dysmorphism

• hypotelorism
• blepharophimosis
• slight ptosis
• epicanthal folds
• microstomia
• dysmorphic ears
• cleft palate

 unilateral brachial neuritis

Differential diagnosis

 blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES)(FOXL2 associated)

Pathology

 germline mutations in the gene septin 9 (SEPT9) in six families with HNA linked to chromosome 17q25.

Septins (SEPTs) are implicated in formation of the cytoskeleton, cell division and tumorigenesis.

References

 Kuhlenbaumer G, Hannibal MC, Nelis E, Schirmacher A, Verpoorten N, Meuleman J, Watts GD, Vriendt ED, Young P, Stogbauer F, Halfter H, Irobi J, Goossens D, Del-Favero J, Betz BG, Hor H, Kurlemann G, Bird TD, Airaksinen E, Mononen T, Serradell AP, Prats JM, Broeckhoven CV, Jonghe PD, Timmerman V, Ringelstein EB, Chance PF. Mutations in SEPT9 cause hereditary neuralgic amyotrophy. Nat Genet. 2005 Oct;37(10):1044-1046. PMID: 16186812