title: Comparison of Methods of Initial Ascertainment in 58 Cases of Propionic Acidemia Enrolled in the Inborn Errors of Metabolism Information System Reveals Significant Differences in Time to Evaluation and Symptoms at Presentation.
abstract: To compare time to evaluation and symptoms at diagnosis of propionic acidemia (PA) by method of ascertainment, and to explore correlations between genotype and biochemical variables.
  
  
  
  Clinical symptoms, genotype, and biochemical findings were analyzed retrospectively in 58 individuals with PA enrolled in the Inborn Errors of Metabolism Information System (IBEM-IS) based on the type of initial ascertainment: abnormal newborn screening (NBS), clinical presentation (symptomatic), or family history.
  
  
  
  The average age at initial evaluation and treatment was significantly younger in patients ascertained via abnormal NBS compared with those referred for clinical symptoms. Furthermore, the majority of individuals ascertained because of abnormal NBS were asymptomatic at diagnosis, compared with a minority of clinical presentations. A notable difference in the frequency of metabolic acidosis at initial presentation was observed between those with abnormal NBS (12.5%; 2 of 16) and those with an abnormal clinical presentation (79%; 19 of 24). The frequency of hyperammonemia was similar in the 2 groups.
  
  
  
  Our data support the continued value of NBS to identify individuals with PA, who are diagnosed and treated earlier than for other modes of ascertainment. There were no statistically significant correlations between genotype and NBS for C3 acylcarnitines. Although expanded use of NBS has allowed for early diagnosis and treatment, long-term outcomes of individuals with PA, especially with respect to mode of ascertainment, remain unclear and would benefit from a longitudinal study.
authors: Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, NC.
authors: Nicholas M
authors: NM
authors: McCrory
authors: Michigan Public Health Institute, Okemos, MI.
authors: Mathew J
authors: MJ
authors: Edick
authors: Division of Genetics, Metabolism, and Genomics, Department of Pediatrics, University of Michigan, Ann Arbor, MI.
authors: Ayesha
authors: A
authors: Ahmad
authors: Division of Genetics, Metabolism, and Genomics, Department of Pediatrics, University of Michigan, Ann Arbor, MI.
authors: Susan
authors: S
authors: Lipinski
authors: Division of Genetics and Metabolism, Department of Pediatrics, University of Wisconsin, Madison, WI.
authors: Jessica A
authors: JA
authors: Scott Schwoerer
authors: Michigan Public Health Institute, Okemos, MI.
authors: Shaohui
authors: S
authors: Zhai
authors: Michigan Public Health Institute, Okemos, MI.
authors: Kaitlin
authors: K
authors: Justice
authors: Michigan Public Health Institute, Okemos, MI.
authors: Cynthia A
authors: CA
authors: Cameron
authors: Division of Genetics and Metabolism, Department of Pediatrics, University of Minnesota, Minneapolis, MN.
authors: Susan A
authors: SA
authors: Berry
authors: Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, NC. Electronic address: loren.pena@duke.edu.
authors: Loren D M
authors: LD
authors: Pena
mesh_terms: D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008661:Metabolism, Inborn Errors / Q000175:diagnosis / Q000235:genetics; D015997:Neonatal Screening / Q000379:methods*; D056693:Propionic Acidemia / Q000175:diagnosis* / Q000235:genetics; D012189:Retrospective Studies; D013997:Time Factors
keywords: C3 acylcarnitine; history; hyperammonemia; hyperglycinemia; longitudinal follow up; natural; newborn screening; nonketotic; organic acidemia