Neonatal ichthyosis-sclerosing cholangitis syndrome caused by a novel CLDN1 mutation: a case report and literature review.

Neonatal ichthyosis-sclerosing cholangitis syndrome (NISCH) is an autosomal recessive disorder characterized by cholestasis, generalized ichthyosis, alopecia, and dental anomalies. As this is a rare syndrome, here we present a case caused by a novel mutation followed by a literature review of all published cases. This retrospective review includes all original articles on the clinical profiles of all 37 cases published through December 2024 using a PubMed search. The patient was a 2-month-old boy who presented with cholestasis, sparse hair, and generalized ichthyosis. Whole-exome sequencing revealed a novel pathogenic variation in exon 1 of the CLDN1 gene: (NM_021101.5) c.36dupT (p.Leu13SerfsTer56). The patient was symptomatically managed, and his condition improved. Among the 37 reported cases, the median age at diagnosis was 60 months (range, 1-636 months). Patients of Moroccan ethnicity were most commonly affected, and c.200_201delTT was the most common mutation. Among the clinical features, ichthyosis was universal (37 of 37 [100%]), followed by jaundice in 70.2% (26 of 37), pruritus in 38.2% (13 of 34), hepatomegaly in 43.3% (13 of 30), and splenomegaly in 23.8% (5 of 21) of patients. Portal hypertension (7 of 35 [20%]) and mental retardation (3 of 21 [14.2%]) were rare. The disease phenotype varied from no liver involvement or transient neonatal cholestasis to end-stage liver disease. Progressive liver disease was reported in 8 patients, five of whom underwent liver transplantation. NISCH is a rare syndrome with variable phenotypes ranging from no liver involvement and transient neonatal cholestasis to advanced liver disease requiring liver transplantation. Therefore, a multidisciplinary approach with close follow-up is required.