Co-existence of phenylketonuria either with maple syrup urine disease or Sandhoff disease in two patients from Iran: emphasizing the role of consanguinity

J Pediatr Endocrinol Metab. 2016 Oct 1;29(10):1215-1219. doi: 10.1515/jpem-2016-0096.

Abstract

Most inborn errors of metabolism (IEMs) are inherited in an autosomal recessive manner. IEMs are one of the major concerns in Iran due to its extensive consanguineous marriages. Herein, we report two patients with two co-existent IEMs: a girl affected by classic phenylketonuria (PKU) and maple syrup urine disease (MSUD) and a male patient affected with Sandhoff disease and PKU, where Sandhoff disease was suspected due to the presence of a cherry-red spot in the eyes at 6 months which is unrelated to PKU. Sequencing of candidate genes in the first patient revealed one novel and three recurrent compound heterozygous mutations of p.Ser231Pro and p.Ala300Ser in the PAH gene and p.Glu330Lys and p.Arg170Cys mutations in the BCKDHB gene. Genetic testing results in the second patient showed previously reported homozygous mutations of p.Arg261Gln in the PAH and p.Arg533Cys mutation in the HEXB gene. Genetic testing confirmed the clinical diagnosis of both diseases in both patients. To the best of our knowledge; this is the first report of the co-existence of two distinct genetic disorders in two individuals from Iran. Co-existent different IEMs in patients complicated the clinical diagnosis and management of the diseases.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Amino Acid Sequence
  • Biomarkers / metabolism
  • Consanguinity*
  • Female
  • Genetic Testing
  • Humans
  • Infant
  • Infant, Newborn
  • Iran
  • Male
  • Maple Syrup Urine Disease / complications*
  • Maple Syrup Urine Disease / diagnosis
  • Maple Syrup Urine Disease / genetics
  • Metabolism, Inborn Errors / genetics
  • Mutation / genetics
  • Pedigree
  • Phenylketonurias / complications*
  • Phenylketonurias / diagnosis
  • Phenylketonurias / genetics
  • Polymerase Chain Reaction
  • Sandhoff Disease / complications*
  • Sandhoff Disease / diagnosis
  • Sandhoff Disease / genetics
  • Sequence Homology, Amino Acid
  • beta-Hexosaminidase beta Chain / genetics

Substances

  • Biomarkers
  • HEXB protein, human
  • beta-Hexosaminidase beta Chain