IHSC, NISCH syndrome
Neonatal ichthyosis-sclerosing cholangitis (NISCH syndrome) is a very rare complex ichthyosis syndrome characterized by scalp hypotrichosis, scarring alopecia, ichthyosis and sclerosing cholangitis. Less than ten patients (from unrelated consanguineous Moroccan families and from Sweden) have been reported so far. The ichthyosis presents with diffuse white scales sparing the skin folds, and is accompanied by scalp hypotrichosis, cicatricial alopecia, and sparse eyelashes/eyebrows. Additional manifestations may include oligodontia, hypodontia and enamel dysplasia. All patients present with neonatal sclerosing cholangitis with jaundice and pruritus, hepatomegaly, and biochemical cholestasis. Overall, the clinical picture mimics biliary atresia (see this term). Portal hypertension, patent extrahepatic bile duct obstruction and splenomegaly may also be present. Histology shows extensive fibrosis and bile duct proliferation. Leukocyte vacuolization is a common finding. The hepatic disease may have variable expressivity, ranging from a progressive disease resulting in liver failure to regression of cholestasis. NISCH syndrome is caused by a mutation in the CLDN1 gene coding for the tight junction protein claudin-1, and shows an autosomal recessive pattern of inheritance. Diagnosis is based on clinical, biochemical and histological features. The differential diagnosis should include Dorfman-Chanarin syndrome and other syndromic forms of ichthyosis (see these terms). Treatments aim at improving symptoms and survival. Liver transplant remains the only effective treatment in case of liver failure. Ichthyosis is managed by hydration of the skin (topical application of creams and emollient oils), retinoids and sunlight exposure.