Clinical course and genetics of syndromic and non-syndromic craniosynostosis
MEDIZINISCHE GENETIK
Authors: Rachwalski, M.; Wollnik, B.; Kress, W.
Abstract
With an incidence of 1:2000-1:3000 births, craniosynostoses are among the most common craniofacial anomalies. Growth inhibition caused by premature fusion of one or more cranial sutures can lead to severe deformities of the skull and facial skeleton. Besides the severe aesthetic problems for the patient, it also has important clinical consequences. These may include raised intracranial pressure, optic nerve atrophy, respiratory, and developmental disorders. Despite major efforts, causative genes (e.g., FGFR1-3, TWIST1) have been detected for only a portion of the autosomal dominantly inherited craniosynostosis syndromes. The etiology of non-syndromic craniosynostosis still remains unclear. The application of next generation sequencing technologies will probably lead to the identification of additional causative genes underlying at the least syndromic forms of craniosynostosis in upcoming years. Due to their clinical complexity, particularly the syndromic forms of craniosynostosis require interdisciplinary care. The only treatment option currently available is craniofacial surgery, which in the long term often fails to remedy the genetically determined pathological growth pattern of complex syndromic craniosynostoses.
Diagnostic value of exome and whole genome sequencing in craniosynostosis
JOURNAL OF MEDICAL GENETICS
Authors: Miller, Kerry A.; Twigg, Stephen R. F.; McGowan, Simon J.; Phipps, Julie M.; Fenwick, Aimee L.; Johnson, David; Wall, Steven A.; Noons, Peter; Rees, Katie E. M.; Tidey, Elizabeth A.; Craft, Judith; Taylor, John; Taylor, Jenny C.; Goos, Jacqueline A. C.; Swagemakers, Sigrid M. A.; Mathijssen, Irene M. J.; van der Spek, Peter J.; Lord, Helen; Lester, Tracy; Abid, Noina; Cilliers, Deirdre; Hurst, Jane A.; Morton, Jenny E. V.; Sweeney, Elizabeth; Weber, Astrid; Wilson, Louise C.; Wilkie, Andrew O. M.
Abstract
Background Craniosynostosis, the premature fusion of one or more cranial sutures, occurs in similar to 1 in 2250 births, either in isolation or as part of a syndrome. Mutations in at least 57 genes have been associated with craniosynostosis, but only a minority of these are included in routine laboratory genetic testing. Methods We used exome or whole genome sequencing to seek a genetic cause in a cohort of 40 subjects with craniosynostosis, selected by clinical or molecular geneticists as being high-priority cases, and in whom prior clinically driven genetic testing had been negative. Results We identified likely associated mutations in 15 patients (37.5%), involving 14 different genes. All genes were mutated in single families, except for IL11RA (two families). We classified the other positive diagnoses as follows: commonly mutated craniosynostosis genes with atypical presentation (EFNB1, TWIST1); other core craniosynostosis genes (CDC45, MSX2, ZIC1); genes for which mutations are only rarely associated with craniosynostosis (FBN1, HUWE1, KRAS, STAT3); and known disease genes for which a causal relationship with craniosynostosis is currently unknown (AHDC1, NTRK2). In two further families, likely novel disease genes are currently undergoing functional validation. In 5 of the 15 positive cases, the (previously unanticipated) molecular diagnosis had immediate, actionable consequences for either genetic or medical management (mutations in EFNB1, FBN1, KRAS, NTRK2, STAT3). Conclusions This substantial genetic heterogeneity, and the multiple actionable mutations identified, emphasises the benefits of exome/whole genome sequencing to identify causal mutations in craniosynostosis cases for which routine clinical testing has yielded negative results.