Biochemical and molecular results. A. Biochemical collagen analysis was performed on collagens produced by the patients dermal fibroblasts, which were grown for 16 hrs in the presence of 14C-Proline. Radioactively labelled intracellular and secreted fibrillar collagen proteins were isolated and mature collagens were obtained by pepsin digestion. Foetal secreted (left panel) as well as intracellular (right panel) mature type I collagen revealed a normal electrophoretic pattern when compared to a control (C) sample. Also for the unprocessed, secreted type I procollagen a normal electrophoretic migration pattern was observed (data not shown). B. ArrayCGH analysis on a 1M SurePrint G3 Human CGH Microarray revealed a homozygous deletion of the entire CREB3L1 gene in the affected foetus III:4. C. Expression level analysis by RT-qPCR was performed in duplicate on total RNA extracted from three biological replicates of the fibroblast cell lines from foetus III:4 and three controls (C1, C2 and C3) (LightCycler480 and RealTime ready DNA Probe Master Mix, Roche). The expression level of each investigated gene was quantified using qbasePLUS (Biogazelle). HPRT1, RLP13a and YWHAZ were applied as reference targets. RT-qPCR for foetus III:4 confirmed the total absence of CREB3L1 expression when compared to control samples (C1, C2 and C3). DGKZ has two alternative (tissue-specific) isoforms.