Test ID: FCDC
Cri-du-chat Syndrome, 5p15.2 Deletion, FISH
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
As an aid in the diagnosis of cri-du-chat syndrome, in conjunction with CMS/8696 Chromosome Analysis, For Congenital Disorders, Blood
Detecting cryptic translocations involving 5p15.2 that are not demonstrated by conventional chromosome studies
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Flourescence In Situ Hybridization (FISH)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
5p15.0
Cat like cry
Cree do sha
Cri du chat
Cry of the cat
FISH
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Provide a reason for referral with each specimen. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.
Forms:
1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
2. If not ordering electronically, submit a Cytogenetics/AFP Congenital Disorders Request Form (Supply T238) with the specimen.
Advise Express Mail or equivalent if not on courier service.
Submit only 1 of the following specimens:
Specimen Type: Amniotic fluid
Container/Tube: Amniotic fluid container
Specimen Volume: 20-25 mL
Collection Instructions:
1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted. Provide gestational age at the time of amniocentesis.
2. Discard the first 2 mL of amniotic fluid.
Additional Information:
1. Place the tubes in a Styrofoam container (Supply T329).
2. Fill remaining space with packing material.
3. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.
4. Bloody specimens are undesirable.
5. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
6. Results will be reported and also telephoned or faxed, if requested.
Specimen Type: Autopsy
Container/Tube: Sterile container with sterile Hank's balanced salt solution (Supply T132), Ringer's solution, or normal saline
Specimen Volume: 4 mm diameter
Collection Instructions:
1. Wash biopsy site with an antiseptic soap.
2. Thoroughly rinse area with sterile water.
3. Do not use alcohol or iodine preparations.
4. Biopsy specimens are best taken by punch biopsy to include full thickness of dermis.
Specimen Type: Blood
Container/Tube: Green top (sodium heparin)
Specimen Volume: 5 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Other anticoagulants are not recommended and are harmful to the viability of the cells.
Specimen Type: Chorionic villi
Container/Tube: 15-mL tube containing 15 mL of transport media
Specimen Volume: 20-25 mg
Collection Instructions:
1. Collect specimen by the transabdominal or transcervical method.
2. Transfer the chorionic villi to a Petri dish containing transport medium (Supply T095).
3. Using a stereomicroscope and sterile forceps, assess the quality and quantity of the villi and remove any blood clots and maternal decidua.
Specimen Type: Fixed cell pellet
Container/Tube: Sterile container with a 3:1 fixative (methanol:glacial acetic acid)
Specimen Volume: Entire specimen
Specimen Type: Products of conception or stillbirth
Container/Tube: Sterile container with sterile Hank's balanced salt solution (Supply T132), Ringer's solution, or normal saline
Specimen Volume: 1 cm(3) of placenta (including 20 mg of chorionic villi) and a 1-cm(3) biopsy specimen of muscle/fascia from the thigh
Collection Information: If a fetus cannot be specifically identified, collect villus material or tissue that appears to be of fetal origin.
Additional Information: Do not send entire fetus.
Forms: Final Disposition of Fetal/Stillborn Remains form (if fetal specimen is sent) in Special Instructions
Specimen Type: Skin biopsy
Container/Tube: Sterile container with sterile Hank's balanced salt solution (Supply T132), Ringer's solution, or normal saline
Specimen Volume: 4 mm diameter
Collection Instructions:
1. Wash biopsy site with an antiseptic soap.
2. Thoroughly rinse area with sterile water.
3. Do not use alcohol or iodine preparations.
4. A local anesthetic may be used.
5. Biopsy specimens are best taken by punch biopsy to include full thickness of dermis.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | Clotted blood |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Ambient (preferred) | |
| Refrigerated | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Cri-du-chat syndrome is associated with a deletion on the short arm of chromosome 5 (5p-). The syndrome can be suspected in infants with a plaintive, mewing cry, low birth weight, and failure to thrive. The weak kittenlike cry that gives name to the syndrome is at least partly due to anatomic abnormalities of the larynx and although the cry changes with time, it does not become normal. Facial features include microcephaly, round face, low-set ears, strabismus, hypertelorism (wide-set eyes), and epicanthus (a vertical fold of skin on either side of the nose). The hands and feet are small, and the hands often have a single crease extending across the palm (simian crease). With age, premature gray hair, dental malocclusion, inguinal hernia, distasis recti, (a separation of the left and right side of the rectus abdominis muscle), and scoliosis are common. Affected individuals’ intelligence varies widely from mild-to-severe mental retardation.
FISH studies are highly specific and do not exclude other chromosome abnormalities. We recommend that patients suspected of having cri-du-chat syndrome also have conventional chromosome studies (CMS/8696 Chromosomes Analysis, for Congenital Disorders, Blood) performed to rule out other chromosome abnormalities or translocations.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
An interpretive report will be provided.
Interpretation Provides information to assist in interpretation of the test results
Any individual with a normal signal pattern (2 signals) in each metaphase is considered negative for a deletion in the region tested by this probe (see Cautions).
Any patient with a FISH signal pattern indicating loss of the critical region will be reported as having a deletion of the region tested by this probe.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Because this FISH test is not approved by the FDA, it is important to confirm cri-du-chat syndrome diagnoses by other established methods, such as clinical history or physical evaluation.
Additional critical genes associated with cri-du-chat syndrome may lie distal to the loci in this probe set, and this test may give normal results if a microdeletion occurs outside the region tested by this probe. If this test is normal and the patient’s phenotype is consistent with cri-du-chat syndrome, subtelometric FISH analysis may be warranted (FRTEL/82583 Subtelomeric Region Anomalies, FISH).
Supportive Data
FISH analysis was performed on a series of 10 patient peripheral blood or amniotic fluid samples and results were compared to cytogenetic or FISH telomere analyses and the patient’s phenotype. Using a probe for the cri-du-chat (CDC) region at 5p15.2, this FISH analysis identified a deletion in 6 patients with a phenotype consistent with cri-du-chat syndrome or a cytogenetic or telomere 5p deletion. Four additional patients with chromosome abnormalities involving chromosome 5, but not containing the 5p15.2 deletion, were further characterized using this probe set. This demonstrated the probe’s ability to define other chromosome 5 rearrangements in this region that are not consistent with 5p15.2 deletion. In a group of 34 patient samples (peripheral blood, tissue, or amniotic fluid) with a normal karyotype or FISH telomere analysis results, no deletions of the CDC region were identified. Two patients with normal results using this probe set were identified to have a more proximal 5p deletion using a telomere FISH analysis (see Cautions).
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Van Dyke DL, Witkor A: Clinical cytogenetics. In Laboratory Medicine. 2nd edition. Edited by K McClatchey. Baltimore, MD. Williams & Wilkins, 2002, Chapter 26
2. Jones K: Deletion 5p syndrome. In Smith’s Recognizable Patterns of Human Malformation. 6th edition. Philadelphia, Elsevier Saunders, 2005
3. Mainardi PC, Perfumo C, Cali A, et al: Clinical and molecular charcterisation of 80 patients with 5p deletion: genotype-phenotype correlation. J Med Genet 2001;38:151-158
Method Description Describes how the test is performed and provides a method-specific reference
The identification of 5p deletions is based on FISH analysis of the loci (D5S721 and D5S23) on the short arm of chromosome 5. Metaphase cells are examined for the presence of the 2 loci at 5p15.2 (green signal) and the control probe (EGR1) at 5p31 (orange signal). In metaphase cells with a deletion, the abnormal (deleted) chromosome 5 will exhibit only a control probe signal, while signals for both the critical region and control probes will be present on the normal chromosome 5 homolog. (Crifasi PA, Michels VV, Driscoll DJ, et al: DNA fluorescent probes for diagnosis of velocardiofacial and related syndromes. Mayo Clin Proc 1995;195[70]:1148-1153)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Samples processed Monday through Sunday. Results reported Monday through Friday, 8 a.m.-5 p.m. CST.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
88271 x 2-DNA probe, each
88273-Chromosomal in situ hybridization
88291-Interpretation and report
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 23254 | Specimen | 31208-2 |
| 23255 | Specimen ID | N/A |
| CG049 | Source | N/A |
| 23257 | Order Date | N/A |
| CG051 | Reason For Referral | 42349-1 |
| 23259 | Method | In Process |
| 23260 | Result | In Process |
| 23261 | Interpretation | 69965-2 |
| 23262 | Amendment | In Process |
| 23263 | Consultant | N/A |
| 23264 | Released Date | N/A |
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