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BA Schwartz, HM Engel, AL Shanske; Panocular Abnormalities in an Infant With a Direct Duplication (14)(q13q24) . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2402.
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Purpose: We examined a newborn with an intrachromosomal duplication of the mid-portion of 14q, who had a unique syndrome. Methods: Case report. BS was the 2735 gm product of a term pregnancy delivered spontaneously to a 15-year-old mother. Newborn examination showed microcephaly and dysmorphic features including short neck with redundant nuchal fold, micrognathia, low-set pinna and bilateral simian creases. He had hypoplastic maculae, corneal haze, blepharophimosis and iris-lens-retinal colobomas. Echocardiographic findings were consistent with Tetralogy of Fallot. Ultrasonography demonstrated absence of the corpus callosum and right renal agenesis. The child expired after ten days because of cardiopulmonary and renal failure. Post-mortem examination showed no additional anomalies. Results: Chromosomal analysis of peripheral blood revealed an abnormal male karyotype 46,XY,dir dup(14)(q13q24), with a direct tandem duplication of segments q13 to q24. Parental karyotypes were requested, but only a maternal sample was available and was normal. FISH studies using a chromosome 14 painting probe confirmed the origin of duplication. Conclusions: Most partial duplications result from unbalanced translocations or pericentric inversions and fall into proximal or distal syndromes. We have described the second de novo case of a tandem interstitial duplication of 14q. Our patient had many features of the CHARGE association (colobomas, heart defects, atresia choanae, growth or mental retardation, genital and ear abnormalities). Similarities between CHARGE and partial 14q duplications suggest the presence of a locus for a gene in this region. North et al., 1995, reported a child with CHARGE and a de novo inverted duplication (14)(q22-q24.3). Disruption of developmental genes in this area (i.e. TGFß3, CHX10 and ZNF46) could result from their proximity to duplication breakpoints. Percin et al., 2000, reported the mapping of a human microphthalmia locus on 14q24.3, cloning of CHX10 at this locus, and identification of recessive CHX10 mutations in 2 families with non-syndromic microphthalmia, cataracts and iris abnormalities. They demonstrated that loss of CHX10 function is panocular in its effects. Although ocular expression of CHX10 is limited to the neuroretina, non-retinal abnormalities may be secondary to failure of the neuroretina to produce a CHX10-dependent factor essential for eye formation. Support: Research to Prevent Blindness
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