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Test Code
1529
Test Name
Dyssegmental Dysplasia, Silverman-Handmaker 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
SJS1; DDSH
Description

HSPG2 related disorders - Schwartz-Jampel syndrome, type 1 (SJS1; MIM 255800) and dyssegmental dysplasia, Silverman-Handmaker type (DDSH; MIM 224410) are autosomal recessive disorders caused by mutations in the HSPG2 gene. This gene codes for perlecan, a basement membrane heparan sulfate proteoglycan.

Schwartz-Jampel syndrome, type 1 (SJS1) is a chondrodysplasia with associated myotonia. The disorder is characterized by postnatal short stature and dysmorphic fixed facies with pursed lips, bowed long bones, low set ears, blepharophimosis and spinal abnormalities that may include platyspondyly, coronal cleft vertebrae, kyphoscoliosis and lumbar lordosis. The metaphyses of long bones may be widened. The myotonia is progressive and it may be accompanied by muscular hypertrophy or weakness. Contractures of the hips, shoulders, wrists, fingers and toes may occur.

Dyssegmental dysplasia, Silverman-Handmaker type (DDSH) is a neonatal lethal skeletal dysplasia. Clinical findings include short, bowed long bones, small chest, anisospondyly, dyssegmental dysplasia, flat face with posteriorly rotated ears, micrognathia, cleft palate and reduced joint mobility. Patients may also have encephalocele, pulmonary hypoplasia and talipes equinovarus.

SJS1 and DDSH are allelic disorders. The differences in the severity of these two disorders are thought to be due to the complete lack of secreted functional perlecan in DDSH and secretion of some functional protein in SJS1.
Testing Schedule
Monday-Friday
Genes
HSPG2
MIM
224410
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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