Published online July 1, 2008
PEDIATRICS Vol. 122 No. 1 July 2008, pp. 210-211 (doi:10.1542/peds.2008-0325)

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LETTER TO THE EDITOR

A False-positive Newborn Screening Result: Goat's Milk Acidopathy

Kimberly A. Chapman, MD, PhD
Jaya Ganesh, MD
Can Ficicioglu, MD, PhD
Section of Biochemical Genetics
Children's Hospital of Philadelphia
Philadelphia, PA 19104

To the Editor.—

With the increase in the number of diseases screened in newborn screening (NBS) programs, an increase in false-positive results has been noted.¹ We encountered a 12-day-old female patient who presented with a positive NBS result for maple syrup urine disease secondary to goat milk consumption.

Our patient initially had NBS results that revealed an elevated phenylalanine level (2.5 mg/dL [reference: <2.3 mg/dL]); thus, the filter-paper test was repeated and showed elevated valine (637 nmol/mL [reference range: 93–321 nmol/mL]) and leucine (381 nmol/mL [reference range: 42–188 nmol/mL]) levels. At 12 days of age, this infant was growing and feeding well without lethargy. The infant had been started on undiluted goat's milk, feeding every 3 to 4 hours since birth, because of a family history of cow's milk intolerance. Initial testing results were consistent with metabolic acidosis (bicarbonate: 17 mmol/L), an elevated serum urea nitrogen level (34 mg/dL [reference range: 20–24 mg/dL]), and no alloisoleucine but twice the normal valine, leucine, and isoleucine levels (505, 249, and 120 nmol/mL, respectively [reference range for each: 17–106 nmol/mL]).

Electrolyte levels and acidosis resolved on soy formula and hydration overnight (bicarbonate: 25 mmol/L; serum urea nitrogen: 22 mg/dL). As a result, the findings were felt to be consistent with goat's milk acidosis secondary to elevated protein and acid load on the infant's kidneys. Harrison et al² described a similar patient in 1979 whose condition also resolved with hydration and a more appropriate feeding regimen. With the increased sensitivity in NBS, this report adds to the list of possible dietary causes for false-positive NBS results. Because false-positive NBS results increase parental anxiety and can change parent-child relationships, recognition of possible dietary causes is important.^1,3,4

REFERENCES

1. Tarini BA, Christakis DA, Welch HG. State newborn screening in the tandem mass spectrometry era: more tests, more false-positive results. Pediatrics.2006; 118 (2):448 –456[Abstract/Free Full Text]
2. Harrison HL, Linshaw MA, Bergen JS, McGeeney T. Goat milk acidosis. J Pediatr.1979; 94 (6):927 –929[CrossRef][Web of Science][Medline]
3. Sorenson JR, Levy HL, Mangione TW, Sepe SJ. Parental response to repeat testing of infants with "false-positive" results in a newborn screening program. Pediatrics.1984; 73 :183 –187[Abstract/Free Full Text]
4. Waisbren SE, Albers S, Amato S, et al. Effect of expanded newborn screening for biochemical genetic disorders on child outcomes and parental stress. JAMA.2003; 290 :2564 –2572[Abstract/Free Full Text]

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PEDIATRICS (ISSN 1098-4275). ©2008 by the American Academy of Pediatrics

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This Article Extract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Chapman, K. A. Articles by Ficicioglu, C. Search for Related Content PubMed PubMed Citation Articles by Chapman, K. A. Articles by Ficicioglu, C. Related Collections Office Practice Social Bookmarking                         What's this?