Related Experiment Video
Updated: Aug 7, 2026
07:36
Modeling Encephalopathy of Prematurity Using Prenatal Hypoxia-ischemia with Intra-amniotic Lipopolysaccharide in Rats
Published on: November 20, 2015
Anencephaly and spina bifida: an etiologic hypothesis
Birth Defects Original Article Series
|February 1, 1971
Summary
Anencephaly and spina bifida show increased incidence in matrilineal relatives, suggesting cytoplasmic inheritance. Recurrence risks and twin discordance point to potential cytoplasmic gene mutations.
Area of Science:
- Developmental biology
- Genetics
- Reproductive medicine
Background:
- Anencephaly and spina bifida are severe congenital malformations.
- Previous studies have indicated familial aggregation of these defects.
Purpose of the Study:
- To investigate the inheritance patterns of anencephaly and spina bifida.
- To explore the potential genetic and etiological factors underlying these neural tube defects.
Main Methods:
- Analysis of familial incidence data for anencephaly and spina bifida.
- Comparison of recurrence risks in siblings versus matrilineal relatives.
- Evaluation of concordance rates in affected twins.
Main Results:
- Increased incidence of anencephaly and spina bifida observed in matrilineal relatives.
- Sibling recurrence risk estimated at 4-5%.
- Affected twins frequently exhibit discordance for these malformations.
Conclusions:
- Findings suggest a significant role for cytoplasmic inheritance in anencephaly and spina bifida.
- Potential involvement of cytoplasmic genetic abnormalities or mutations is indicated.
- Further research into non-Mendelian inheritance patterns is warranted.
More Related Videos
Related Concept Videos
01:30Neurulation
Neurulation is the embryological process which forms the precursors of the central nervous system and occurs after gastrulation has established the three primary cell layers of the embryo: ectoderm, mesoderm, and endoderm. In humans, the majority of this system is formed via primary neurulation, in which the central portion of the ectoderm—originally appearing as a flat sheet of cells—folds upwards and inwards, sealing off to form a hollow neural tube. As development proceeds, the anterior...
01:21Nondisjunction
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers. Nondisjunction is common during anaphase I or anaphase II of meiosis. Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold sister...
01:07Teratogenicity
The ability of a drug to produce structural deformations and functional abnormalities in the developing embryo or the fetus is called teratogenicity, and the drug producing this effect is known as a teratogen. Teratogenic effects include stillbirth, miscarriage, intrauterine growth restriction, and neurocognitive delay. A teratogen may affect the embryo at different stages of development, which is important in determining the type and extent of the damage. During blastocyst formation, the early...
01:26Bacterial Meningitis II: Pathophysiology
Bacterial meningitis typically begins when pathogens such as Neisseria meningitidis and Streptococcus pneumoniae colonize the nasopharynx and invade the bloodstream. This process is facilitated by bacterial virulence factors, such as polysaccharide capsules, which resist phagocytosis and complement-mediated killing. Less commonly, bacteria reach the central nervous system via contiguous spread from infections like otitis media or sinusitis, through congenital or acquired dural defects, or...
01:22Cerebral Edema ll: Pathophysiology
Vasogenic edema is a major form of cerebral edema characterized by abnormal accumulation of fluid in the brain’s extracellular space due to disruption of the blood–brain barrier (BBB). The BBB is a specialized structure composed of endothelial cells connected by tight junctions, supported by astrocytic endfeet and a basement membrane. Under normal conditions, it tightly regulates the movement of ions, proteins, and solutes between the bloodstream and brain parenchyma. When this barrier loses...