Brief Description

Lysosomal Storage Disorders (LSDs) are genetic disorders resulting in enzyme deficiencies within the lysosomes of the body's cells. Lysosomes are the microscopic recycle bins in the cells that store, break down and recycle large unwanted molecules by utilizing very specific enzymes. The presence of an LSD results in an accumulation of these large molecules in the lysosomes resulting in their dysfunction, and ultimately irreversible damage to muscles, nerves and/or certain organs in the body. There are treatments available for these disorders if caught early before symptoms begin to appear in the infant.

The Missouri State Public Health Laboratory screens for the following Lysosomal Storage Disorders:

  • Pompe
  • Gaucher
  • Fabry
  • MPS-I

Laboratory Unit

Methodology

Digital Microfluidics

Specimen Collection

Missouri newborn screening samples must only be collected on the Food and Drug Administration (FDA) approved blood collection forms that must be pre-purchased from the MSPHL. The optimum collection time is between 24 and 48 hours-of-age. The instructions for collecting the samples are listed on the back of the collection form. All 5 circles on the filter paper need to be filled with blood from one side and then air dried for at least 3 hours in a horizontal position without allowing the blood to touch any surface during drying, including other parts of the card (see image). 
See "Rules for Collection".

Storage/Transport

Store the dried blood samples at room temperature in the envelopes provided by the MSPHL and transport within 24 hours of collection.

Acceptable Specimen Type(s)

Initial Screen (the red form) or Repeat Screen (the green form)

Test Request Form(s)

Included in kit

Possible Results

Normal:  The final newborn screening reports are mailed to the submitter and physician of record.
Borderline Risk: Repeat the newborn screen. If, however, the infant is sick or displays signs of metabolic distress, the physician may wish to conduct diagnostic testing instead of, or in addition to the repeat screen. The final newborn screening reports are mailed to the submitter and physician of record.
High Risk: Diagnostic testing and consultation with a metabolic specialist is needed. Final results are phoned and faxed to physician/health care provider and appropriate follow up center. Follow up centers are contracted by the Department of Health and Senior Services (DHSS) for follow up tracking, testing, diagnosis, and counseling.

Reference Range

Disorder Enzyme Expected value
Pompe Acid alpha glucosidase (GAA) >8.0 µmol/L/hr
Gaucher Glucosylceramidase (GBA) >7.0 µmol/L/hr
Fabry Alpha galactosidase (GLA) >8.0 µmol/L/hr
MPS-I Alpha L iduronidase (IDUA) >2.0 µmol/L/hr

Unacceptable Conditions

Interfering Substances

Specimen collection prior to 24 hours of age, prematurity, and illness can all affect the newborn screening results. “No Result” is reported on those specimens collected before 24 hours of age.

Lysosomal enzyme activities are not reliable in premature newborns with <34 weeks gestation or birthweight <2000 grams. A repeat newborn screen at 28 days of age is necessary.
False positive results may be caused by:

  • Improper drying
  • Samples placed in plastic prior to drying
  • Delayed transit or exposure to heat and humidity

Result Reported

1 to 3 working days after receipt of specimen

Fees

$85 charge – for full panel of screening disorders

CPT Codes

82657

LOINC/SNOMED Codes

N/A

Additional Information