Chondrodysplasia Punctata II: a case with clinical characteristics and no mutation on the EBP gene

Includes bibliographical references (pages 88-125)X-linked dominant Chondrodysplasia Punctata (CDPX2) also known as Conradi-Hunermann???Happle Syndrome is a rare human genetic disorder resulting from disfunction of Emopamil Binding Protein (EBP). EBP is better known as Sterol isomerase (SI),which it acts as the 2nd to last enzyme in the 30-step Cholesterol biosynthetic pathway. SI converts ???8-cholestenol to ???7- cholestenol (lathostenol) and zymostenol to ???7, 24-cholestadenol. A disturbance of any of the 30 metabolic steps result in the accumulation of bioactive precursors. At present, there are over 40 known distinct mutations along the EBP gene, although there is no clear genotype-phenotype correlation. These intermediates may have teratogens effects on a devolving fetus, producing any of several birth defects. These include a variety of Chondrodysplasia syndromes, such as CDPX1, CDPX2 and RCP. Trademark features of CDPX2 include cataracts, stippling of the vertebrae and the ribs, ichthyosis, and prominent lines of Blaschko. Individuals diagnosed with CDPX2 may exhibit a diverse series of phenotypes and Biochemical and DNA analysis are the two methods to confirm the disorder. In this study, I performed DNA analysis on an individual diagnosed with CDPX2 due to phenotypic characteristics present at birth and persisting through adulthood. My findings present no known mutation within EBP to neither explain nor validate the CDPX2 diagnosis. A close examination of current literature brings forth several possibilities to explain a case where an individual shows clinical features, but does not have a mutated EBP gene