Description:

HFI is an autosomal recessive disease caused by deficiency of aldolase B (fructose 1-phosphate aldolase), the isozyme expressed in tissues such as liver, kidney, and intestine that metabolizes fructose. The gene for aldolase B contains 9 exons and is located on chromosome 9. Exon 5 contains the two most common mutations: A149P and A174D. It was reported by Cross et al. (The Lancet, 335:306-309 (1990)) that 67% of the HFI alleles are A149P and 16% are A174D. The A149P mutation is more common in Northern European populations and the A174D mutation has been found in Italy, Switzerland, and Yugoslavia. In the Swiss population, the frequency of HFI is one in 11,000 to 100,000 live births.

Reasons for Referral:

• Confirmation of a clinical diagnosis
• Carrier testing
• Family history

Testing Methodology:

A PCR-based assay is used to amplify all exons and the immediately adjacent intronic regions of the ALDOB gene. Direct sequence analysis of PCR products is performed in both the forward and reverse directions using automated fluorescent dideoxy sequencing methods.

Specimen Requirements

Blood: EDTA (purple-top) tubes: Adult: 14 cc; Child: 6 cc; Infant: 2-3 cc

Turnaround Time:

Index: 3 weeks
Known Familial Mutation: 2 weeks

CPT Codes and Prices:

Index: 83904x18, 83898x9, 83912, 83891, 83894x2
Known Familial Mutation: 83904x4, 83898x2, 83912, 83891, 83894x2

Shipping Information

Forms:

>> Gene Sequencing Requisition or Mitochondrial Requisition - Mitochondrial Diagnostic Checklist is included
>> Prenatal Requisition

Test Codes:

Index: 3125
Known Familial Mutation: 3126
Prenatal: 3127

Medical Genetics Laboratories
Baylor College of Medicine · Houston, TX 77030
Phone: 1-800-411-GENE · Fax: 713-798-6584
E-mail: