Syndromes, Disorders and Maternal Risk Factors Associated with Neural Tube Defects (II)

Fetal Brain Development: Regulating Processes and Related Malformations

This paper describes the contemporary state of knowledge regarding processes that regulate normal development of the embryonic–fetal central nervous system (CNS). The processes are described according to the developmental timetable: dorsal induction, ventral induction, neurogenesis, neuronal migration, post-migration neuronal development, and cortical organization. We review the current literature on CNS malformations associated with these regulating processes. We specifically address neural tube defects, holoprosencephaly, malformations of cortical development (including microcephaly, megalencephaly, lissencephaly, cobblestone malformations, gray matter heterotopia, and polymicrogyria), disorders of the corpus callosum, and posterior fossa malformations. Fetal ventriculomegaly, which frequently accompanies these disorders, is also reviewed. Each malformation is described with reference to the etiology, genetic causes, prenatal sonographic imaging, associated anomalies, differential diagnosis, complimentary diagnostic studies, clinical interventions, neurodevelopmental outcome, and life quality.

Overview of Neural Tube Defects: Gene–Environment Interactions, Preventative Approaches and Future Perspectives

Neural tube defects (NTDs) are the second most common congenital malformations of humans, characterized by impaired development of the central nervous system. Even though the etiology of most birth defects remains undetermined, genetic and environmental risk factors in the background of NTDs have been identified and extensively reported. On top of genetic and nutritional risks which include mutations in both coding and non-coding regions and maternal folate status, respectively, recent years have seen a rise in the identification of a variety of teratogens that could be implicated in NTD development. These include polycyclic aromatic hydrocarbons, arsenic, pesticides, maternal hyperthermia and antibiotics as well as pain and seizure medication. With an increase in understanding of teratogens leading to NTD formation, preventative and treatment approaches have witnessed great advances throughout the years. While the most common preventative approach includes folic acid food fortification as well as suggested inositol supplementation, treatment and management approaches differ greatly depending on the developmental stage and the site of the lesion and include prenatal surgery, stem cell transplantation and postnatal surgery. Because NTDs still represent a large health and financial burden for the patient and society as a whole, it is crucial to investigate potential risk factors and develop novel approaches in order to fully prevent this category of disorders.

Neural tube defects: Different types and brief review of neurulation process and its clinical implication

Neural Tube Defects are the most typical congenital malformations, with almost 300,000 cases annually worldwide. The incidence varies amongst geographical ranges from 0.2 to up to 11 per 1000 live births. In India, incidence is reportedly higher in north than south and can be attributable to diet and genetic variances. Etiology is multifactorial. Severe forms of whitethorn are allied with syndromes. Primary neurulation and secondary neurulation are the most crucial steps in the formation and closure of the neural tube; any interruption can lead to mild to severe NTDs depending on the level of insult during embryogenesis. Various molecular and cellular events take place simultaneously for neural tube bending and closure of the neural tube. Neurological deficit in the newborn is contingent on the level of defect and severity of the structures affected. Survival of the newborn also depends on the severity of the lesion. Folic acid supplementation in all prospective mothers, preferably 4 weeks before conception and at least 12 weeks after conception, can prevent NTDs in folic responsive groups. But there is a significant number of other causes leading to neural tube defects apart from folic acid. Hydrocephalus is the commonest abnormality allied with NTDs in syndromic cases.

Closure of a giant anterior sacral meningocele with an omental flap in a patient with Marfan syndrome: case report

Anterior sacral meningoceles (ASMs) are rare lesions often associated with connective tissue disorders. These lesions are typically treated posteriorly via closure of the dural stalk. However, given their insidious nature, ASMs can be quite large on presentation, and this approach may not provide adequate decompression. In this case report, the authors describe the successful treatment of a large ASM through drainage and watertight closure of the cyst with an omental flap. A 43-year-old woman with a history of Marfan syndrome and a large ASM was referred for neurosurgical intervention. The ASM was filling the pelvic cavity and causing severe compression of the bladder. The patient underwent surgical decompression of the cyst through an anterior transabdominal approach and closure of the fistulous tract with a pedicled omental flap. This is the first reported case of successful closure of an ASM with an omental flap. At the 6-month follow-up, the ASM had not recurred on imaging and the patient's symptoms had resolved. Anterior sacral meningoceles are rare lesions that often require neurosurgical intervention. Although most can be treated posteriorly, large ASMs compressing the abdominal or pelvic organs may require a transabdominal approach. Moreover, ASMs with wide dural stalks may benefit from closure with an omental flap.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

Anterior Sacral Meningocele Masquerading as an Ovarian Cyst: A Rare Clinical Presentation Associated with Marfan Syndrome

Anterior sacral meningocele is a very rare clinical entity characterized by herniation of a meningeal sac through a sacrococcygeal defect. We report a case of a 20-year old female with Marfan syndrome who presented with abdominal distention that was misdiagnosed as an ovarian cyst on pelvic ultrasound. Pelvic magnetic resonance (MR) imaging showed large, well-defined multiloculated intrasacral and presacral cysts communicating via two separate broad necks and extending through defects in anterior aspect of sacral vertebrae. This case emphasizes that anterior sacral meningocele should be considered in the differential diagnosis of cases with pelvic cysts particularly in patients with underlying connective tissue disorders. Because severe neurologic complications or even death may occur without proper preoperative planning in such cases, MR imaging should always be performed for evaluation and characterization of pelvis cystic lesions.

Biome depletion in conjunction with evolutionary mismatches could play a role in the etiology of neurofibromatosis 1

Neurofibromatosis 1 (NF1) arises de novo in a striking 30-50% of cases, pointing toward an environmental etiology, though none has been clearly identified. The Biome Depletion Theory posits that the absence of mutualistic and commensal organisms within the human body coupled with modern lifestyle alterations may have profoundly deleterious effects, inclusive of immunologic derangement that is thought to result in allergy, atopy, and numerous autoimmune diseases. Biome depletion has been implicated as a factor in the etiology of both multiple sclerosis and autism spectrum disorders; biome reconstitution, i.e. replenishment of the biome with certain keynote species, is being used in the treatment of these and other autoimmune states. Neurofibromatosis 1 has been associated with allergy, various autoimmune states, multiple sclerosis, and autism. Recent research has posited that NF1, multiple sclerosis and autism may all arise from disturbances in the neural crest during gestation. This paper hypothesizes that there is indirect evidence that a highly inflammatory uterine state may precipitate epigenetic changes in vulnerable NF-related genes in the course of fetal development. The etiology of NF1 may lie in the absence of immunomodulation by commensal and mutualistic species once ubiquitously present in the environment, as well as through adoption of a modern lifestyle that contributes to chronic inflammation. Replenishment of helminths and other missing organisms to the human biome prior to conception as well as addressing nutritional status, psychological stress, and environmental exposures may prevent the development of NF1.

Familial Currarino syndrome associated with Hirschsprung disease: two cases of a mother and daughter

Currarino syndrome with Hirschsprung disease (CS-HD) is extremely rare. We present the first family with CS-HD. Case 1: A 28-year-old woman was admitted with severe abdominal distension and dyspnea. She was diagnosed with anal stenosis, hemisacrum, anterior sacral meningocele (ASM), tethered cord (TC), and short-segment aganglionosis. She underwent the modified Duhamel operation after meningocele repair and cord detethering. A bicornuate uterus, bilateral ovarian dermoid cysts, and small rectal duplication were also noted intraoperatively. Case 2: The daughter of case 1 was admitted for abdominal distension and anal stenosis at the age of 17 days. Studies revealed a hemisacrum, ASM, TC, presacral mass, atrial septal defect, polyp in the right nasal cavity, right vesicoureteral reflux, and short-segment aganglionosis. She underwent the modified Soave operation at the age of 1 year and 4 months after meningocele repair, cord detethering, and resection of the presacral mass (epidermoid cyst). In both cases, the aganglionic segments were confirmed by preoperative rectal suction biopsy and postoperative pathological examination on full-thickness rectal specimens. Some causal genes for Currarino syndrome (CS) and Hirschsprung disease (HD) are currently investigated. Thus far, 10 CS-HD cases have been reported, including 6 cases of familial CS. However, all the patients had sporadic HD. Recent reports suggest that anomalies of the enteric nerve system contribute to postoperative constipation in CS cases.

Recommendations for folate intake in women: implications for public health strategies

Folate deficiency has been associated with anemia and other adverse outcomes in pregnancy such as neural tube defects. The current recommendations for prevention of such outcomes are difficult to achieve through diet only, and folic acid supplementation and food fortification are feasible public health strategies. However, it is necessary to determine the usual diet and supplement use among women of reproductive age, including an accurate assessment of other dietary micronutrients. In addition to the beneficial effects observed in randomized clinical trials, health risks to the population have also been widely evaluated and discussed in the scientific community: for a minority to benefit from fortification programs, many are exposed to high folic acid intake levels.