Figure 3.

Liver histological findings and NOTCH2 compound heterozygous mutations detected in patient 3. (A) Low magnification showing preserved lobular architecture of the liver parenchyma and lack of significant fibrosis (Trichrome stain, 40x). The portal tracts (arrows) seen at this magnification fail to show either significant inflammation or any obvious pathology. (B) Higher magnification (400x) of the portal tract to show absence of the bile duct and also any lack of ductular reaction. Occasional lymphocytes or histocytes can be seen in the portal tract. Few glycogenated hepatocytic nuclei can be seen in the periportal region (H&E stain). (C) Immunostain for CK7 highlights the absence of the native bile duct and shows intense staining of the periportal hepatocytes (200x). (D) Sanger sequence trace of codons 1720–1722 are shown. Patient 3 is heterozygous for a base change (TCA>TTA, in red) in NOTCH2, resulting in a S1741L (c. 5222C>T) missense heterozygous mutation. Proband's father is heterozygous for the same mutation whereas proband's mother is wild-type (WT). (E) Conservation of S1741 across species. The amino acid sequence of 1733–1749 of human NOTCH2 is shown and compared to the corresponding sequences of eight vertebrate orthologs and paralogs. Amino acid positions identical to human genome are highlighted in yellow. (F) Sanger sequence trace of codons 1881–1883 are shown. Patient 3 is heterozygous for a base change (CAC>TAC, in red) in NOTCH2, resulting in a H1882Y (c.5644C>T) missense heterozygous mutation, Proband's mother is heterozygous for the same mutation whereas proband's father is wild-type (WT). (G) Conservation of H1882Y across species. The amino acid sequence of 1874–1890 of human NOTCH2 is shown and compared to the corresponding sequences of eight vertebrate orthologs and paralogs. Amino acid positions identical to human genome are highlighted in yellow. H1882 is conserved among all species examined.