Fetal growth retardation, hydrocephalus, hypoplastic multilobed lungs, and other anomalies in 4 sibs

Syndromes and Disorders Associated with Omphalocele (III): Single Gene Disorders, Neural Tube Defects, Diaphragmatic Defects and Others

Omphalocele can be associated with single gene disorders, neural tube defects, diaphragmatic defects, fetal valproate syndrome, and syndromes of unknown etiology. This article provides a comprehensive review of omphalocele-related disorders: otopalatodigital syndrome type II; Melnick-Needles syndrome; Rieger syndrome; neural tube defects; Meckel syndrome; Shprintzen-Goldberg omphalocele syndrome; lethal omphalocele-cleft palate syndrome; cerebro-costo-mandibular syndrome; fetal valproate syndrome; Marshall-Smith syndrome; fibrochondrogenesis; hydrolethalus syndrome; Fryns syndrome; omphalocele, diaphragmatic defects, radial anomalies and various internal malformations; diaphragmatic defects, limb deficiencies and ossification defects of skull; Donnai-Barrow syndrome; CHARGE syndrome; Goltz syndrome; Carpenter syndrome; Toriello-Carey syndrome; familial omphalocele; Cornelia de Lange syndrome; C syndrome; Elejalde syndrome; Malpuech syndrome; cervical ribs, Sprengel anomaly, anal atresia and urethral obstruction; hydrocephalus with associated malformations; Kennerknecht syndrome; lymphedema, atrial septal defect and facial changes; and craniosynostosismental retardation syndrome of Lin and Gettig. Perinatal identification of omphalocele should alert one to the possibility of omphalocele-related disorders and familial inheritance and prompt a thorough genetic counseling for these disorders.

Genetics of human hydrocephalus

Human hydrocephalus is a common medical condition that is characterized by abnormalities in the flow or resorption of cerebrospinal fluid (CSF), resulting in ventricular dilatation. Human hydrocephalus can be classified into two clinical forms, congenital and acquired. Hydrocephalus is one of the complex and multifactorial neurological disorders.

A growing body of evidence indicates that genetic factors play a major role in the pathogenesis of hydrocephalus. An understanding of the genetic components and mechanism of this complex disorder may offer us significant insights into the molecular etiology of impaired brain development and an accumulation of the cerebrospinal fluid in cerebral compartments during the pathogenesis of hydrocephalus. Genetic studies in animal models have started to open the way for understanding the underlying pathology of hydrocephalus. At least 43 mutants/loci linked to hereditary hydrocephalus have been identified in animal models and humans. Up to date, 9 genes associated with hydrocephalus have been identified in animal models. In contrast, only one such gene has been identified in humans. Most of known hydrocephalus gene products are the important cytokines, growth factors or related molecules in the cellular signal pathways during early brain development. The current molecular genetic evidence from animal models indicate that in the early development stage, impaired and abnormal brain development caused by abnormal cellular signaling and functioning, all these cellular and developmental events would eventually lead to the congenital hydrocephalus.

Owing to our very primitive knowledge of the genetics and molecular pathogenesis of human hydrocephalus, it is difficult to evaluate whether data gained from animal models can be extrapolated to humans. Initiation of a large population genetics study in humans will certainly provide invaluable information about the molecular and cellular etiology and the developmental mechanisms of human hydrocephalus.

This review summarizes the recent findings on this issue among human and animal models, especially with reference to the molecular genetics, pathological, physiological and cellular studies, and identifies future research directions.

Insights into the pathogenesis of hydrocephalus from transgenic and experimental animal models

Hydrocephalus is a progressive brain disorder characterized by abnormalities in the flow of cerebrospinal fluid (CSF) and ventricular dilatation that leads to cerebral atrophy, and if left untreated, can be fatal. Genetic mutations, congenital malformations, infectious diseases, intracerebral hemorrhages and tumors are common conditions resulting in hydrocephalus. Although the causes of obstructive hydrocephalus are better understood, the mechanisms resulting in chronic, progressive communicating congenital and acquired hydrocephalus are less well understood. In this regard, recent studies in transgenic (tg) mice suggest that increased expression of cytokines such as TGF-beta1 might play an important role by disrupting the vascular extracellular matrix (ECM) remodeling, promoting hemorrhages, and altering the reabsorption of CSF. In this context, the main objective of this manuscript is to provide an overview on the cellular and molecular mechanisms of hydrocephalus based on studies derived from tg and experimental animal models.

Omphalocele in Miller-Dieker syndrome: expanding the phenotype

We report on a patient prenatally diagnosed with omphalocele, mild cerebral ventriculomegaly, nuchal fold thickening, and cystic changes in the umbilical cord who was found postnatally to have lissencephaly type I. Prenatal chromosome analysis showed a normal male karyotype; however, postnatal high resolution banding and FISH analysis, using a probe for locus D17S379 in chromosome region 17p13.3, demonstrated a deletion at 17p13.3 consistent with Miller-Dieker syndrome (MDS). A review documented four more cases with MDS/isolated lissencephaly/17p-, with omphalocele. Because MDS is a contiguous gene disorder, we speculate that a gene or genes in this region have a major role in the closure of the lateral folds or the return of the midgut from the body stalk to the abdomen at 5-11 weeks of gestation. Prenatal diagnosis of omphalocele with mild ventriculomegaly should prompt FISH analysis for a deletion in 17p13.3.

Hydrocephalus, skeletal anomalies, and mental disturbances in a mother and three daughters: a new syndrome

We report on a family in which a mother and her 3 daughters have delayed psychomotor development and/or psychosis, hydrocephalus with white matter alterations, arachnoid cysts, skeletal anomalies consisting of brachydactyly, and Sprengel anomaly. Biochemical and cytogenetic analyses were normal on all 4 patients. The pattern of inheritance, clinical manifestations, and variability of expression suggest that this is a new hydrocephalus syndrome possibly transmitted as an X-linked dominant trait.