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Test Code
1847
Test Name
Chondrodysplasia, Grebe Type
CPT Codes
81479
Expected Turnaround Time
Typically 2 to 4 weeks from receipt of a sample in the laboratory. All cases involving ongoing pregnancies will be expedited.
Clinical Utility
Genetic analysis to provide a molecular diagnosis of this disorder. Recommended for individuals with a personal and/or family history of this disorder to ensure appropriate treatment and establish recurrence risk for family members.
Specimen and Container Info

Non-Prenatal Specimens

Preferred/Alternate

Specimen Type

Containers

Volume

Preferred Specimen Type

Whole Blood

Lavender Top (EDTA)

3 mL

Alternate Specimen Type

Genomic DNA

1.5 mL Tube

3 µg (at a concentration of at least 30 ng/µl), preferably in TE solution.

Alternate Specimen Type

Fibroblasts

T-25 Flasks

2 confluent T-25 flasks, filled to capacity

Alternate Specimen Type

Saliva (Whole blood is recommended for CNV)

DNA Self-Collection Kit or Oragene Saliva Collection Kit for Young Children

Follow kit instructions (www.dnagenotek.com)

Prenatal Specimens

Either specimen type below is acceptable.

Specimen Type

Containers

Volume

Cultured cells

T-25 Flasks

2 confluent T-25 flasks derived from amnio or CVS samples.

Genomic DNA

1.5 mL Tube

3 µg (at a concentration of at least 30 ng/µl), preferably in TE solution.

NOTE: For specimens from outside of North America, the preferred specimen type is Genomic DNA. HNL Genomics does not recommend shipping whole blood or cultured cells from any location other than the United States, Canada, or Mexico.
Transport Instructions
  • Transport at room temperature within 24 hours.
  • If the specimen cannot be transported to the lab within 24 hours, refrigerate for up to 72 hours.
  • Do not freeze or expose to extreme temperatures, refrigerate for up to 72 hours if cannot be transported to lab within 24 hours. 
Stability Requirements

Room Temperature

24 hours

Refrigerated

72 hours
Causes for Rejection
  • Improperly labeled specimen (minimum of two patient identifiers)
  • Inappropriate specimen type
  • Incomplete or incorrect test request form
  • Insufficient volume
  • Specimen has leaked in transit
  • Specimen without a test order
Methodology
Next Generation Sequencing and Copy Number Variation Analysis
Performing Location
Genomics - Snowdrift
Alternate Names
AMDH; AMDG
Description

Acromesomelic dysplasia, Hunter-Thompson type (AMDH), Chondrodysplasia, Grebe type (AMDG) and Fibular hypoplasia and complex brachydactyly

Acromesomelic dysplasia, Hunter-Thompson type (AMDH; MIM 201250) and Chondrodysplasia, Grebe type (AMDG, MIM 200700) are autosomal recessive disorders caused by mutations in the growth/differentiation factor 5 (GDF5) gene.  AMDH and AMDG are characterized by severe prenatal onset growth retardation restricted to the limbs. The middle and distal segments of the limbs are more severely affected than the proximal parts. In AMDH, the lower limbs are more profoundly affected than the upper limbs and large joint dislocations are common.  In AMDG, hypomelia is more severe, but the upper and lower limbs are equally affected.  Reduction or absence of the proximal and middle phalanges of the fingers and toes is seen in both disorders; however, this anomaly is more prominent in AMDG with all fingers and toes ball-shaped and functionless. The axial skeleton is not affected and intelligence is normal in these disorders.

Fibular hypoplasia and complex brachydactyly (Du Pan syndrome; MIM 228900) is another autosomal recessive disorder caused by mutations in GDF5. The main findings in this disorder are severe reduction or absence of the fibula and complex brachydactyly.

Multiple synostoses syndrome 2 (SYNS2; MIM 610017), symphalangism, proximal, 1B (SYM1B; MIM 615298), brachydactyly, type A1, C (BDA1C; MIM 615072), brachydactyly, type A2 (BDA2; MIM 112600) and brachydactyly, type C (BDC; MIM 113100) are also caused by mutations in GDF5.
Testing Schedule
Monday-Friday
Genes
GDF5
MIM
200700
Disease Group
Skeletal Disorders
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
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