Related Experiment Video

Updated: Jun 15, 2026

In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila
06:41

In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila

Published on: August 20, 2019

13.9K

Patterns of congenital anomalies among individuals with trisomy 13 in Texas

Diego Diaz1, Renata H Benjamin1, Maria Luisa Navarro Sanchez1

  • 1Department of Epidemiology, Human Genetics and Environmental Sciences, UTHealth School of Public Health, Houston, Texas, USA.

American Journal of Medical Genetics. Part A
|March 22, 2021
PubMed

Insights

This study analyzed birth defect combinations in trisomy 13. Microcephaly, brain defects, nasal anomalies, and polydactyly frequently co-occurred, aiding understanding of trisomy 13 phenotypes.

Area of Science:

  • Genetics
  • Developmental Biology
  • Medical Genetics

Background:

  • Trisomy 13 (Patau syndrome) is a severe chromosomal disorder.
  • Limited population-based data exists on co-occurring birth defects in trisomy 13.
  • Understanding defect patterns is crucial for diagnosis and management.

Purpose of the Study:

  • To investigate the frequency and patterns of co-occurring birth defects in individuals with trisomy 13.
  • To identify specific combinations of birth defects that occur more often than expected by chance.
  • To refine the phenotypic spectrum of trisomy 13.

Main Methods:

  • Analysis of 736 individuals with trisomy 13 from the Texas Birth Defects Registry (1999-2014).
  • Calculation of observed-to-expected ratios for combinations of one to four additional birth defects.
  • Adjustment for non-specific birth defect clustering and sensitivity analyses for live births.

Main Results:

  • The most prominent combination of defects included microcephaly, brain malformations (e.g., holoprosencephaly), nasal anomalies, and polydactyly.
  • Many high-ratio combinations involved known trisomy 13 features like scalp defects (aplasia cutis) and heart anomalies.
  • Results remained consistent when analyzing live births only.

Conclusions:

  • Identified specific co-occurring birth defect patterns in trisomy 13 beyond expected clustering.
  • Findings contribute to a more detailed understanding of the trisomy 13 phenotype.
  • May inform improved screening, genetic counseling, and future research for trisomy 13.

More Related Videos

Navigating MARRVEL, a Web-Based Tool that Integrates Human Genomics and Model Organism Genetics Information09:37

Navigating MARRVEL, a Web-Based Tool that Integrates Human Genomics and Model Organism Genetics Information

Published on: August 15, 2019

10.1K
Eye Tracking Young Children with Autism09:03

Eye Tracking Young Children with Autism

Published on: March 27, 2012

46.1K

Related Concept Videos

Karyotyping01:17

Karyotyping

Describing the number and physical features of chromosomes can reveal abnormalities that underlie genetic diseases. This description is facilitated by special staining techniques that produce a particular banding pattern on each chromosome. State-of-the-art techniques make this approach even more powerful, enabling the detection of individual genes that cause disease.A Simple Chromosome Staining Technique Provides Valuable Scientific InsightSome genetic diseases can be detected by looking at...
Meiosis I01:49

Meiosis I

Meiosis is a carefully orchestrated set of cell divisions, the goal of which—in humans—is to produce haploid sperm or eggs, each containing half the number of chromosomes present in somatic cells elsewhere in the body. Meiosis I is the first such division, and involves several key steps, among them: condensation of replicated chromosomes in diploid cells; the pairing of homologous chromosomes and their exchange of information; and finally, the separation of homologous chromosomes by a...
Nondisjunction01:29

Nondisjunction

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.
Nondisjunction01:21

Nondisjunction

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...
Nondisjunction01:29

Nondisjunction

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.
Genomic Imprinting and Inheritance02:30

Genomic 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...