Eur J Med Genet. 2019 Dec;62(12):103588. doi: 10.1016/j.ejmg.2018.11.022. Epub 2018 Nov 22. https://www.ncbi.nlm.nih.gov/pubmed/30472488

Phenotypic spectrum associated with SPECC1L pathogenic variants: new families and critical review of the nosology of Teebi, Opitz GBBB, and Baraitser-Winter syndromes.

Bhoj EJ¹, Haye D², Toutain A³, Bonneau D⁴, Nielsen IK⁵, Lund IB⁵, Bogaard P⁶, Leenskjold S⁷, Karaer K⁸, Wild KT⁹, Grand KL⁹, Astiazaran MC¹⁰, Gonzalez-Nieto LA¹⁰, Carvalho A¹¹, Lehalle D¹², Amudhavalli SM¹³, Repnikova E¹⁴, Saunders C¹⁴, Thiffault I¹⁴, Saadi I¹⁵, Li D¹⁶, Hakonarson H¹⁶, Vial Y², Zackai E⁹, Callier P¹¹, Drunat S², Verloes A¹⁷.

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Abstract

The SPECC1L protein plays a role in adherens junctions involved in cell adhesion, actin cytoskeleton organization, microtubule stabilization, spindle organization and cytokinesis. It modulates PI3K-AKT signaling and controls cranial neural crest cell delamination during facial morphogenesis. SPECC1L causative variants were first identified in individuals with oblique facial clefts. Recently, causative variants in SPECC1L were reported in a pedigree reported in 1988 as atypical Opitz GBBB syndrome. Six families with SPECC1L variants have been reported thus far. We report here eight further pedigrees with SPECC1L variants, including a three-generation family, and a further individual of a previously published family. We discuss the nosology of Teebi and GBBB, and the syndromes related to SPECC1L variants. Although the phenotype of individuals with SPECC1L mutations shows overlap with Opitz syndrome in its craniofacial anomalies, the canonical laryngeal malformations and male genital anomalies are not observed. Instead, individuals with SPECCL1 variants have branchial fistulae, omphalocele, diaphragmatic hernias, and uterus didelphis. We also point to the clinical overlap of SPECC1L syndrome with mild Baraitser-Winter craniofrontofacial syndrome: they share similar dysmorphic features (wide, short nose with a large tip, cleft lip and palate, blepharoptosis, retrognathia, and craniosynostosis), although intellectual disability, neuronal migration defect, and muscular problems remain largely specific to Baraitser-Winter syndrome. In conclusion, we suggest that patients with pathogenic variants in SPECC1L should not be described as “dominant (or type 2) Opitz GBBB syndrome”, and instead should be referred to as “SPECC1L syndrome” as both disorders show distinctive, non overlapping developmental anomalies beyond facial communalities.

Copyright © 2018. Published by Elsevier Masson SAS.

KEYWORDS:

Bicornuate uterus; MID1; Nosology; Omphalocele; Opitz BBBG syndrome; SPECC1L; Teebi hypertelorism syndromePMID: 30472488 PMCID: PMC6594898 [Available on 2020-12-01] DOI: 10.1016/j.ejmg.2018.11.022