Vanishing White Matter, Dysmyelinating, and Hypomyelinating Leukodystrophy


Test Details
TEST CODE NGS375
TEST METHODOLOGY NGS
TAT (TURNAROUND TIME) 2 - 4 weeks
GENES 62
CPT CODE 81405, 81406 x3, 81479
PRICE $1995
RECOMMENDED MNG KITS
  • SINGLE Blood Genetic Testing
  • Buccal Swab Genetic Testing

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Clinical Information
Clinical Significance

Vanishing white matter disease (VWM) is one of the most prevalent inherited childhood leukoencephalopathies, also named Childhood Ataxia with Central Nervous System Hypomyelination/ Vanishing White Matter disease (CACH/VWM).

The disorder is characterized by ataxia, spasticity, and variable optic atrophy. The phenotypic range includes a prenatal/congenital form, a subacute infantile form (onset age <1 year), an early childhood onset form (onset age 1-5 years), a late childhood/ juvenile onset form (onset age 5-15 years), and an adult onset form.

The prenatal/congenital form is characterized by severe encephalopathy. In the later onset forms, initial motor and intellectual development is normal or mildly delayed followed by neurologic deterioration with a chronic progressive or subacute course. Chronic progressive decline can be exacerbated by rapid deterioration during febrile illnesses or following head trauma or major surgical procedures, or by acute psychological stresses such as extreme fright.

The classical phenotype is characterized by early childhood onset of chronic neurological deterioration, dominated by cerebellar ataxia. VWM is unusual because of its clinically evident sensitivity to febrile infections, minor head trauma, and acute fright, which may cause rapid neurological deterioration and unexplained coma. Most patients die a few years after onset.

Relevant Diseases
  • Vanishing White Matter, Dysmyelinating, and Hypomyelinating Leukodystrophy

Specimen Information
Acceptable Sample Types
  • Muscle
  • Cultured Fibroblasts
  • Whole Blood - EDTA
  • Extracted DNA - Leukocytes
  • Buccal Cells
Sample Preparation: (1) Blood specimens: Draw blood in an EDTA tube. Preferred volume: 4 milliliters (adults and pediatrics), Minimum volume: 2 milliliters; (2) DNA extracted from leukocytes, muscle, or fibroblasts: Preferred quantity: 4 micrograms, Minimum quantity: 3 micrograms (Genomic DNA should be eluted in sterile Dnase/Rnase free water or TE. The A260:A280 ratio should be 1.8-2.0.); (3) 2 T-25 flasks of fibroblasts; (4) 50-75 milligrams muscle snap frozen in liquid nitrogen and maintained at -80┬░Celsius or below. (5) Skin biopsy (Fibroblasts will be cultured from skin specimen for genetic testing): Skin biopsy may be taken from the inner forearm with a sterile skin punch (2-5 millimeters) or at incision site of muscle biopsy. Site is sterilized with alcohol swabs only (other reagents will inhibit cell isolation/growth). Biopsy site may be anaesthetized with 2% lidocaine with epinephrine. Depth of punch is 2mm. Transfer skin biopsy into 15 milliliter conical tube filled with sterile culture media. (6) Buccal cells.
Shipping Condition: MNG SmartKits are available for free shipping of specimens. Please see our website for details. If you are not using a MNG SmartKit: (1) Blood specimens should be shipped in a secure container at room temperature. (2) Extracted DNA should be shipped priority overnight at ambient temperature. (3) T-25 flasks containing fibroblasts should be shipped in an insulated container at room temperature. Flasks should be completely filled with media and cells should be ~90% confluent. Fibroblast samples must be certified free from Mycoplasma. MNG is able to perform this service for a small charge (See TC05). (4) Muscle samples should be shipped frozen in an insulated container with 5-7 lbs dry ice. (5) Buccal cells should be shipped in a secure container at room temperature. (6) Skin Biopsy: Conical containing the skin specimen should be shipped in a secure container with cold pack (DO NOT FREEZE). All samples should be shipped overnight at the proper temperature for receipt by our lab Monday thru Saturday (No Sunday or holiday deliveries accepted).

Genes Assessed
ACADS
ACO2
ADSL
AP4B1
B3GALNT2
COX7B
CYP27A1
DARS
DARS2
DDOST
DHFR
DNM1L
EIF2B1
EIF2B2
EIF2B3
EIF2B4
EIF2B5
ELOVL4
ERCC6
FA2H
FKRP
FKTN
FOLR1
FOXG1
GFM1
GJB1
GJC2
GLUL
GPR56
HSPD1
HTRA1
IDUA
KCNT1
LAMA2
LARGE
MARS2
MCOLN1
MEF2C
MLYCD
MTTP
MUT
NOTCH3
PAH
PEX7
PHGDH
PLP1
POLG
POLR3A
POLR3B
POMGNT1
POMT1
POMT2
PTEN
RMND1
SLC16A2
SLC25A12
SLC33A1
SOX10
STXBP1
TUBB4A
TYMP
UBE2A

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