De novo chromosome 7q36.1q36.2 triplication in a child with developmental delay, growth failure, distinctive facial features, and multiple congenital anomalies: a case report.

The child presented here had developmental delay, distinctive facial features, multiple congenital anomalies, and 7q36.1q36.2 triplication. This triplication, which was found to be de novo, has not been previously described and is believed to result in the observed phenotype. The triplicated region harbors the GALNTL5, GALNT11, KMT2C, XRCC2, and ACTR3B genes. GALNT11 encodes a membrane-bound polypeptide N-acetylgalactosaminyltransferase that can O-glycosylate NOTCH1 leading to the activation of the Notch signaling pathway. Therefore, increased GALNT11 dosage can potentially alter the Notch signaling pathway explaining the pathogenicity of 7q36 triplication. Studying further cases with similar genomic rearrangements is needed to make final conclusions about the pathogenicity of this triplication.