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Test Code PHOX2B seq PHOX2B Sequencing

Clinical System Name

PHOX2B Sequencing

Synonyms

Congenital central hypoventilation syndrome (CCHS)

Description

Congenital Central Hypoventilation Syndrome (CCHS) is a rare disorder that affects breathing (alveolar hypoventilation) and autonomic regulation. It often occurs in newborns and less frequently as a milder condition in young children and adults. Individuals affected with CCHS require assistance for breathing via a ventilator 24 hours a day or only during sleep. Tracheostomy along with assisted ventilation is especially recommended for young children (Weese-Mayer et al. 2014). Some individuals with CCHS also have associated Hirschsprung disease and/or neuroblastomas in up to 20% and 6% of cases, respectively. CCHS is also known as Ondine's curse and Haddad syndrome; the latter refers to the co-occurrence of CCHS and Hirschsprung disease (Lai and Schroer 2008), but both terms are not commonly used. The prevalence of CCHS is estimated at 1,000 individuals worldwide, but this may be an underestimate because individuals with a milder phenotype are underdiagnosed (Weese-Mayer et al. 2010).

Sample Requirements

Specimen: Whole Blood

Container(s): Lavender Top/EDTA, Yellow/ACD

Preferred Vol: 3 - 5 mL

Minimum Vol: 1 mL for small infants

 

Specimen: DNA

Container(s): Sterile plastic tube

Preferred Vol: 5µg -10 µg of purified DNA at a concentration of at least 20 µg/ml for NGS and Sanger tests and at least 5 µg of purified DNA at a concentration of at least 100 µg/ml for gene-centric aCGH, MLPA, and CMA

Processing Instructions

Reject due to: Hemolyzed blood

Spin: N

Aliquot: N

Temp: 2-8 C

Storage location: Refrigerate in CPA refrigerator Sendouts rack.

 

Off-site collection: Send whole blood refrigerated.

Stability

 

Specimen Type Temperature Time
Whole blood Room temp 3 d
Whole blood Refrigerated 7 d
Whole blood Frozen N
Extracted DNA Room temp 3-4 d
Extracted DNA Refrigerated 1 y
Extracted DNA Frozen Indefinitely

 

Availability

STAT TAT
N 2-3 w

 

Performing Laboratory

PreventionGenetics

Department

Department:     PreventionGenetics, 3800 S. Business Park Ave., Marshfield, Wisconsin 54449

Phone Number:    (715) 387-0484

 

 

Reference Range

Interpretive report is provided.

Methodology

Method: Bi-Directional Sanger Sequencing

 

This Sanger sequencing assay is able to detect the expansion of the polyalanine repeat region and single or small nucleotide changes that are causative for CCHS.

Special Instructions

Links to:

 

PreventionGenetics

Send Out Instructions

Reference Test Name: Congenital Central Hypoventilation Syndrome (CCHS) via the PHOX2B gene
Reference Test Number: 1173
Instructions: Ship whole blood overnight, ambient temperature. PreventionGenetics accepts Saturday delivery