The S37P mutation swaps one amino acid for another, a serine for a proline, in just one part at the end of the resulting NatA protein subunit. Other mutations have since been discovered in very small number of cases worldwide with the most prevalent being Arg83Cys mutation. Mutations to this gene changes the structure of the protein, which makes it less effective at N-terminal acetylation than the normal protein, causing a multitude of effects for the baby, as N-terminal acetylation is one of the most common protein modifications in humans, occurring on approximately 80% of all human proteins. Diagnosis
Whole exome sequencing is the definitive diagnostic method used to confirm OS. History
Halena Black had her first son, Kenny Rae, in 1979. Being that he was her first born child, Black did not notice that something was wrong. Kenny Rae Black passed in 1980, right before his first birthday and was the first known infant to die from Ogden syndrome. However, it did not end there. Halena Black continued to have children and in 1987 she had her next boy, Hyrum. From the start, Black noticed that Hyrum had the same characteristics as Kenny Rae but thought it was due to the fact that they were brothers. Like Kenny Rae, Hyrum passed before his first birthday. It was only until Blacks daughters began having children of their own that she realized something was not right.
A few reports of genetically transmitted colpocephaly are also found in literature. Some of these are of two siblings, monozygotic twins, and non-identical twins. The authors suggest a genetic origin with an autosomal or X-linked recessive inheritance rather than resulting from early prenatal disturbances. Diagnosis
Presentation
Colpocephaly is characterized by disproportionately large occipital horns of the lateral ventricles (also frontal and temporal ventricles in some cases). MRI and CT scans of patients demonstrate abnormally thick gray matter with thin poorly myelinated white matter. This happens as a result of partial or complete absence of the corpus callosum. Corpus callosum is the band of white matter connecting the two cerebral hemispheres. The corpus callosum plays an extremely important role in interhemispheric communication, thus lack of or absence of these neural fibers results in a number of disabilities.The lemon sign on CT scans of patients refers to the shape of the fetal skull when the frontal bones lose their normal convex contour and appear flattened or inwardly scalloped. This gives the skull a shape similar to that of a lemon. The sign is seen on transverse sonograms of the fetal cranium obtained at the level of the ventricles. A special case is found in literature where lissencephaly, colpocephaly, and septal agenesis are all present together. The CT scans of the patient shows the ventricular system having a unique appearance of a crown of a king. This is referred to as the CROWN SIGN. Prenatal
Diagnosing colpocephaly prenatally is difficult because in many cases signs start to appear after birth.