Zimmermann–Laband syndrome (ZLS)[3] is two different conditions (ZLS, type 1 and ZLS, type 2) that share similar clinical features. It is an extremely rare,[4]autosomaldominant[5]congenital disorder.
Clinical features include gingival fibromatosis, hypoplasia of the distal phalanges, nail dysplasia, joint hypermobility, and sometimes hepatosplenomegaly.[7] The nose and pinnae are usually large and poorly developed, which give individuals with the syndrome characteristic facial features. Intellectual disability may also be seen.[8][6] Gingival fibromatosis is usually present at birth or appears shortly thereafter.[2][6] Both males and females are equally affected.
Genetics
Type 1 ZLS is caused by pathogenic variants (mutations) in a potassium channel gene – KCNH1.[9] Similar pathogenic variants in this gene were previously found to cause Temple–Baraitser syndrome, which shares similar clinical features. This has led many to believe that ZLS, type 1 and TBS are actually the same disorder.[10][11]
Type 2 ZLS is caused by pathogenic variants in the brain isoform of V-type proton ATPase subunit B, ATP6V1B2.[9]
Zimmerman–Laband syndrome is inherited in an autosomal dominant pattern. This means the gene is located on an autosome, and having only one copy of a gene mutation is sufficient to cause the disorder. Individuals with the disorder have a 50% chance of passing it on to their offspring in each pregnancy.
Diagnosis
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^Holzhausen, M; Gonçalves, D; Corrêa, Fde, O; Spolidorio, Lc; Rodrigues, Vc; Orrico, Sr (August 2003). "A case of Zimmermann–Laband syndrome with supernumerary teeth". Journal of Periodontology. 74 (8): 1225–30. doi:10.1902/jop.2003.74.8.1225. ISSN0022-3492. PMID14514238.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Atabek ME, Pirgon O, Sert A, Toy H (2005). "Zimmermann–Laband syndrome in an infant with an atypical histologic finding". Pediatr. Dev. Pathol. 8 (6): 654–7. doi:10.1007/s10024-005-0048-1. PMID16267629. S2CID41832725.
^ abKortüm F, Caputo V, Bauer CK, Stella L, Ciolfi A, Alawi M, et al. (June 2015). "Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome". Nature Genetics. 47 (6): 661–667. doi:10.1038/ng.3282. hdl:2108/118197. PMID25915598. S2CID12060592.
^Bramswig NC, Ockeloen CW, Czeschik JC, van Essen AJ, Pfundt R, Smeitink J, et al. (October 2015). "'Splitting versus lumping': Temple-Baraitser and Zimmermann-Laband Syndromes". Human Genetics. 134 (10): 1089–1097. doi:10.1007/s00439-015-1590-1. PMID26264464. S2CID253982917.
^Mégarbané A, Al-Ali R, Choucair N, Lek M, Wang E, Ladjimi M, Rose CM, Hobeika R, Macary Y, Temanni R, Jithesh PV, Chouchane A, Sastry KS, Thomas R, Tomei S, Liu W, Marincola FM, MacArthur D, Chouchane L1 (2016) Temple-Baraitser Syndrome and Zimmermann–Laband Syndrome: one clinical entity? BMC Med Genet. 17(1):42. doi: 10.1186/s12881-016-0304-4