Related Experiment Video
Updated: Jun 19, 2026
09:16
Array Comparative Genomic Hybridization (Array CGH) for Detection of Genomic Copy Number Variants
Published on: February 21, 2015
Chromosome imbalances in syndromic hearing loss
A L P M Catelani1, A C V Krepischi, C A Kim
1Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, Brazil.
Clinical Genetics
|October 8, 2009
Summary
Genetic testing using array-based comparative genomic hybridization (aCGH) identified chromosomal microimbalances in individuals with syndromic hearing impairment. This method is recommended for diagnosing the causes of deafness.
Area of Science:
- Genetics
- Genomics
- Audiology
Background:
- The etiology of hearing impairment remains unknown in many patients.
- Syndromic hearing impairment often presents with complex and atypical clinical features.
- Identifying genetic causes is crucial for understanding and managing hearing loss.
Purpose of the Study:
- To investigate chromosomal abnormalities in individuals with syndromic hearing impairment.
- To identify novel genes and chromosomal regions associated with hearing loss.
- To evaluate the utility of array-based comparative genomic hybridization (aCGH) in diagnosing hearing impairment.
Main Methods:
- Screening of 29 individuals with syndromic hearing impairment using 1-Mb array-based comparative genomic hybridization (aCGH).
- Analysis of chromosomal copy number variations (CNVs), including de novo and inherited alterations.
- Comparison of genomic data between affected individuals and their parents.
Main Results:
- Rare chromosomal copy number changes were detected in eight out of 29 patients (27.6%).
- Four de novo and four inherited imbalances were identified, implicating specific chromosomal segments (1q23.3-q25.2, 2q22q23, 6p25.3, 11q13.2-q13.4).
- Syndromic deafness is frequently associated with submicroscopic chromosomal imbalances.
Conclusions:
- Array-based comparative genomic hybridization (aCGH) is a valuable tool for identifying the genetic causes of syndromic hearing impairment.
- The identified chromosomal regions harbor potential dosage-sensitive genes contributing to hearing loss.
- Further investigation is warranted to elucidate the role of inherited imbalances in hearing impairment predisposition.
Related Concept Videos
01:17Karyotyping
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...
01:17Karyotyping
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...
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...
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...