Cytogenetics

Director:

Denise Batista, PhD

About the Cytogenetics Laboratory:

In the clinical cytogenetics laboratory several methods are utilized to detect chromosome abnormalities that may confer a phenotypic or reproductive impact. The laboratory performs high-resolution chromosome analysis on peripheral blood specimens. Other tests also include chromosome breakage, fluorescence in situ hybridization (FISH), and microarray analysis. Cytogenetic analysis is performed by certified clinical laboratory specialists and reviewed by a certified Ph.D. clinical cytogeneticist.

Indications for Cytogenetic Analysis:

  • Family history of chromosome anomaly
  • Recurrent spontaneous abortions
  • Infertility
  • Still birth and neonatal deaths
  • Fetal anomalies detected with ultrasound
  • Intellectual disability
  • Dysmorphic features
  • Females with primary or secondary amenorrhea
  • Ambiguous genitalia
  • Ataxia telangiectasia and Fanconi's anemia

Cytogenetic Tests:

Peripheral Blood High Resolution Chromosome Analysis

Lymphocytes are stimulated with mitogens and synchronized to yield elongated chromosomes. These long chromosomes permit high resolution analysis to detect more subtle abnormalities.

Chromosomal Breakage Analysis

Peripheral blood samples are treated with DEB (diepoxybutane) or X-irradiated to induce breakage in individuals with suspected diagnosis of Fanconi's anemia or Ataxia telangiectasia, respectively. The frequency of breaks is compared to a normal control run in parallel and also to our database of positive and negative individuals.

Specimens for this test must be drawn and shipped on Monday for overnight delivery on Tuesday.

Fluorescence in situ hybridization (FISH) Analysis

Fluorescence in situ hybridization (FISH) is used to detect alterations in specific chromosomal regions from metaphase spreads and/or interphase nuclei. These probes show specific changes, such as amplifications, deletions, or translocations of specific genes, loci, or chromosomal regions.

Array SNP-based Analysis

Our microarray platform contains probes targeting single nucleotide polymorphisms (SNPs) and non-polymorphic markers. Both types of probes are utilized to detect copy number changes (CNC), including deletions, duplications, and unbalanced rearrangements. SNP probes provide allelic information and are used to detect copy number neutral loss of heterozygosity (LOH) or uniparental disomy (UPD). Two genotyping measurements, normalized intensity and allelic ratios, are performed utilizing specialized software and allow the identification of CNC and LOH/UPD. The array will not identify balanced rearrangements, including reciprocal and Robertsonian translocations, insertions or inversions, nor will it detect point mutations.

When ordering this test, please include the signed Informed Consent for Genetic Testing Form.

Hours of Operation:

Monday - Friday: 8:30 a.m. to 5:30 p.m. EST

The lab also has limited weekend hours.

Contact Us:

Cytogenetics Laboratory
707 North Broadway
Room 506
Baltimore, MD 21205
Phone: (443) 923-2785

For More Information:

For additional information, please contact Elizabeth Wohler, MS, at Wohler@kennedykrieger.org or (443) 923-2785.