Temple-Baraitser Syndrome and Zimmermann-Laband Syndrome: one clinical entity?
BMC MEDICAL GENETICS
Authors: Megarbane, Andre; Al-Ali, Rashid; Choucair, Nancy; Lek, Monko; Wang, Ena; Ladjimi, Moncef; Rose, Catherine M.; Hobeika, Remy; Macary, Yvette; Temanni, Ramzi; Jithesh, Puthen V.; Chouchane, Aouatef; Sastry, Konduru S.; Thomas, Remy; Tomei, Sara; Liu, Wei; Marincola, Francesco M.; MacArthur, Daniel; Chouchane, Lotfi
Abstract
Background: KCNH1 encodes a voltage-gated potassium channel that is predominantly expressed in the central nervous system. Mutations in this gene were recently found to be responsible for Temple-Baraitser Syndrome (TMBTS) and Zimmermann-Laband syndrome (ZLS). Methods: Here, we report a new case of TMBTS diagnosed in a Lebanese child. Whole genome sequencing was carried out on DNA samples of the proband and his parents to identify mutations associated with this disease. Sanger sequencing was performed to confirm the presence of detected variants. Results: Whole genome sequencing revealed three missense mutations in TMBTS patient: c.1042G > A in KCNH1, c.2131 T > C in STK36, and c.726C > A in ZNF517. According to all predictors, mutation in KCNH1 is damaging de novo mutation that results in substitution of Glycine by Arginine, i.e., p.(Gly348Arg). This mutation was already reported in a patient with ZLS that could affect the connecting loop between helices S4-S5 of KCNH1 with a gain of function effect. Conclusions: Our findings demonstrate that KCNH1 mutations cause TMBTS and expand the mutational spectrum of KCNH1 in TMBTS. In addition, all cases of TMBTS were reviewed and compared to ZLS. We suggest that the two syndromes are a continuum and that the variability in the phenotypes is the result of the involvement of genetic modifiers.
Fused (Stk36) is a Ciliary Protein Required for Central Pair Assembly and Motile Cilia Orientation in the Mammalian Oviduct
DEVELOPMENTAL DYNAMICS
Authors: Nozawa, Yoko Ines; Yao, Erica; Lin, Chuwen; Yang, Jehn-Hsiahn; Wilson, Christopher W.; Gacayan, Rhodora; Chuang, Pao-Tien
Abstract
Background: Motile cilia on the inner lining of the oviductal epithelium play a central role in ovum transport toward the uterus and subsequent fertilization by sperm. While the basic ultrastructure of 9+2 motile cilia (nine peripheral microtubule doublets surrounding a central pair) has been characterized, many important steps of ciliogenesis remain poorly understood.Results: Our previous studies on mammalian Fused (Fu) (Stk36), a putative serine-threonine kinase, reveal a critical function of Fu in central pair construction and cilia orientation of motile cilia that line the tracheal and ependymal epithelia. These findings identify a novel regulatory component for these processes. In this study, we show that Fu is expressed in the multi-ciliated oviductal epithelium in several vertebrates, suggesting a conserved function of Fu in the oviduct. In support of this, analysis of Fu-deficient mouse oviducts uncovers a similar role of Fu in central pair construction and cilia orientation. We also demonstrate that Fu localizes to motile cilia and physically associates with kinesin Kif27 located at the cilium base and known central pair components Spag16 and Pcdp1.Conclusions: Our results delineate a novel pathway for central pair apparatus assembly and add important insight to the biogenesis and function of oviductal motile cilia. Developmental Dynamics 242:1307-1319, 2013. (c) 2013 Wiley Periodicals, Inc.