Rare cause of post-squalene disorder of cholesterol biosynthesis

Errors of cholesterol biosynthesis represent a heterogeneous group of metabolic disorders. The aim of the authors of this article is to present a case of a patient with typical symptoms of a rare post-squalene disorder of cholesterol biosynthesis, its diagnostics and progress in neonatal period. The differential diagnosis of a typical findings on the skin with spontaneous regression ichtyosiform erythroderma, craniofacial dysmorphic features, anomalies of organs or skeletal abnormalities in a newborn may also be the result of a disorder of cholesterol biosynthesis. The final diagnosis is definitely confirmed by  DNA analysis. Prognosis depends on the different enzyme defects of cholesterol biosynthesis pathway, but typically on the post-squalene pathway.     Cholesterol is an important substance that plays a significant role in membrane structure, as well as being the precursor for the synthesis of the steroid hormones and bile acids. Cholesterol synthesis occurs in the cytoplasm and microsomes from the two-carbon acetate group of acetyl coenzyme A (acetyl-CoA). The biosynthesis of cholesterol consists of several reactions. Acetyl-CoA units are converted to mevalonate by a series of reactions. Mevalonate is formed on squalene and then lanosterol.  Lanosterol is converted by two different pathways, either with the creation of 7-dehydrocholesterol, or desmosterol with the creation of cholesterol. Errors of cholesterol biosynthesis represent a heterogeneous group of metabolic disorders that is characterized by multiple dysmorphic features underlining an important role for cholesterol in human embryogenesis and development. The differential diagnosis of atypical findings on the skin in newborn may be the result of disorder of cholesterol biosynthesis. It may be also associated with various dysmorphic features or anomalies including multiple anomalies of congenital and internal organs and skeletal abnormalities. Some of the post-squalene disorders may point to atypical findings on the skin in the form of psoriatic eruptions, psychomotoric delay or laboratory findings as hypocholesterolemia. Key words: newborn; hypocholesterolemia; stigma; chondrodysplasia punctata; ichthyosiform erythroderm

Unusual cause of neonatal intestinal obstruction

There are many causes of intestinal obstruction in the neonatal age. The most common types are mechanical and result from congenital malformations of the gastrointestinal tract. However, functional disorders also occur. In some cases, diagnosis can be made prenatally but in others manifestation occurs after birth. The aim of this article is to present the case of a newborn with intestinal obstruction characterized by microcolon, dilated small bowel and megacystis known as Megacystis-Microcolon-Intestinal Hypoperistalsis syndrome, a very rare cause of intestinal obstruction. So far, less than three hundred cases have been reported in the literature. The prognosis of this syndrome is generally poor with most affected children dying in the neonatal period or infancy. Intestinal obstruction is a serious and life threatening condition. It may be explained by gross anatomical, histological or other abnormalities affecting the gut of the fetus.  Differential diagnosis may also take into account various anatomical, histological, or other abnormalities that may result in the obstruction of gut.  The incidence of intestinal obstruction is estimated at about one in 1500 live births.2 The cause of obstruction can be extrinsic or intrinsic. Atresia is quite common in the anorectal region, while atresia of the stomach occurs rarely. Colonic atresia is a rare condition of bowel obstruction in neonates. Membranous or complete obstruction may be present in the small intestine and may affect multiple sites. Stenosis may result from extrinsic or intrinsic factors. It arises from the failure of physiological rotation or fixation of the intestine in utero. Malrotation is one of the most serious cases, when there is incomplete rotation of the intestine into flexura duodenojejunalis or incomplete rotation of the caecum. Duodenal obstruction may also result when adhesion bands of Ladd straps down the second part of the duodenum. The second group of causes of bowel obstruction in the newborn consists of functional intestinal obstructions. It develops due to defects of bowel inervation and differentiation of ganglion cells. It includes small left colon syndrome or neuronal intestinal dysplasia type A and neuronal intestinal dysplasia type B