Fig. 1

a Clinical picture of the affected probands reported in this study. Note dysmorphic facial phenotype, low forehead and bushy eyebrows. Photos of the patients reported in Orrico et. al. are included for comparison (adapted from [18]) (b) Pedigree of the family showing the two affected siblings (filled symbols; S1 & S2) with homozygous deletions encompassing exons 2–3 of the CNTNAP2 gene. The brother is unaffected (unfilled symbol; S3) and has no detected CNV's. Parents are first cousins and both carry the heterozygous CNTNAP2 deletion (symbols with dots; P), but are phenotypically normal. c PCR gel of the mutant CNTNAP2 gene. A ~700 base pair product spanning the breakpoint could be amplified from the homozygous siblings and heterozygous parent, but not from the unaffected sibling. A Sanger sequencing trace shows the location of the deletion breakpoint. d The wild type CASPR2 protein and predicted functional consequences of CNTNAP2 patient mutations on the CASPR2 protein product. CASPR2 is composed of 1331 amino acids with a number of functional domains including a signal peptide (SP), discoidin/neuropilin homology domain (F5/8 Type C), Laminin G domain (LamG), Epidermal Growth Factor like domain (EGF-like), Fibrinogen domain (Fibrinogen), Transmembrane domain (Transmembrane), and Protein 4.1 homologous binding domain (4.1 m). The exon 2–3 deletion (reported herein), exon 3 deletion [16] and c3709delG mutation [14] all produce truncated proteins due to early stop codons. The exon 2–9 deletion [13] also produces a truncated protein product, however in this case it is due to an in-frame loss of amino acids 33–500