We describe a syndrome of primary microcephaly with simplified gyral pattern in combination with severe infantile epileptic encephalopathy and early-onset permanent diabetes in two unrelated consanguineous families with at least three affected children. Linkage analysis revealed a region on chromosome 18 with a significant LOD score of 4.3. In this area, two homozygous nonconserved missense mutations in immediate early response 3 interacting protein 1 (IER3IP1) were found in patients from both families. IER3IP1 is highly expressed in the fetal brain cortex and fetal pancreas and is thought to be involved in endoplasmic reticulum stress response. We reported one of these families previously in a paper on Wolcott-Rallison syndrome (WRS). WRS is characterized by increased apoptotic cell death as part of an uncontrolled unfolded protein response. Increased apoptosis has been shown to be a cause of microcephaly in animal models. An autopsy specimen from one patient showed increased apoptosis in the cerebral cortex and pancreas beta cells, implicating premature cell death as the pathogenetic mechanism. Both patient fibroblasts and control fibroblasts treated with siRNA specific for IER3IP1 showed an increased susceptibility to apoptotic cell death under stress conditions in comparison to controls. This directly implicates IER3IP1 in the regulation of cell survival. Identification of IER3IP1 mutations sheds light on the mechanisms of brain development and on the pathogenesis of infantile epilepsy and early-onset permanent diabetes.

We present a male newborn (weight 4000 g) who died at age 12 days with a clinical history of persistent hypoglycemia and polycythemia. Clinical examination disclosed somatic hemihypertrophy (left side), a large umbilical hernia, macroglossia, and an intraabdominal tumor, consistent with the diagnosis of Beckwith-Wiedemann syndrome (EMG syndrome) and hemihypertrophy. Necropsy findings included visceromegaly (left kidney and adrenal), cytomegaly of the fetal cortex and nodular arrangement of both adrenals, diffuse nesidioblastosis and islet cell hyperplasia of the pancreas, and persistent glomerulogenesis. The tumor was a cystic pancreatoblastoma attached to the anterior surface of the pancreas. Three other examples of this association, congenital pancreatoblastoma and Beckwith-Wiedemann syndrome, all in males, are on record in the literature, indicating a strong relationship between both conditions.

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