Related Experiment Video
Updated: Jul 19, 2026
09:04
Guide Wire Assisted Catheterization and Colored Dye Injection for Vascular Mapping of Monochorionic Twin Placentas
Published on: September 5, 2011
Pervasive developmental disorder in monozygotic twins.
1Department of Pediatrics, Stanford University School of Medicine, California.
Journal of the American Academy of Child and Adolescent Psychiatry
|November 1, 1990
Summary
Genetic and environmental factors influence pervasive developmental disorder (PDD) expression. This study of monozygotic twins suggests genetics play a role, but environmental factors shape PDD severity and specific symptoms.
Area of Science:
- Developmental Psychology
- Genetics
- Neuroscience
Background:
- Pervasive developmental disorder, not otherwise specified (PDD-NOS) is a complex neurodevelopmental condition.
- Monozygotic (identical) twins share nearly identical genetic material, making them valuable for disentangling genetic and environmental influences.
Observation:
- Two monozygotic twin brothers were diagnosed with PDD-NOS.
- The twins exhibited varying degrees of cognitive and behavioral impairment.
- One twin had a higher number of documented suboptimal pre-, peri-, and postnatal factors.
Findings:
- Genetic predisposition is important in the development of PDD-NOS.
- Nongenetic factors, including suboptimal perinatal events, significantly influence the severity of developmental delay and specific clinical manifestations.
- Environmental influences can modulate the expression of a genetically influenced disorder.
Implications:
- Understanding the interplay between genetics and environment is crucial for PDD-NOS research and intervention.
- This case study highlights the need for comprehensive assessment of environmental factors in individuals with PDD-NOS.
- Further research into specific environmental triggers could lead to targeted prevention and treatment strategies for neurodevelopmental disorders.
More Related Videos
09:16Use of a Video Scoring Anchor for Rapid Serial Assessment of Social Communication in Toddlers
Published on: March 14, 2018
09:51Model Surgical Training: Skills Acquisition in Fetoscopic Laser Photocoagulation of Monochorionic Diamniotic Twin Placenta Using Realistic Simulators
Published on: March 21, 2018
Related Concept Videos
01:43Sex-linked Disorders
Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological deficits, the disorder is considered sex-linked.
01:29Nondisjunction
During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
02:30Genomic Imprinting and Inheritance
Diploid organisms inherit genetic material through chromosomes from both parents. Copies of the same gene are known as alleles. In most cases, both alleles are simultaneously expressed and allow various cellular processes to function optimally. If one of the alleles is missing or mutated, the expression of the other allele can compensate; however, this is not true for all genes.
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
01:43Sex Linked Disorders
Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological deficits, the disorder is considered sex-linked.
01:29Nondisjunction
During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
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...