Hoyeraal-Hreidarsson Syndrome due to PARN Mutations: Fourteen Years of Follow-Up

Pediatr Neurol. 2016 Mar;56:62-68.e1. doi: 10.1016/j.pediatrneurol.2015.12.005. Epub 2015 Dec 19.


Background: Hoyeraal-Hreidarsson syndrome is a dyskeratosis congenita-related telomere biology disorder that presents in infancy with intrauterine growth retardation, immunodeficiency, and cerebellar hypoplasia in addition to the triad of nail dysplasia, skin pigmentation, and oral leukoplakia. Individuals with Hoyeraal-Hreidarsson syndrome often develop bone marrow failure in early childhood. Germline mutations in DKC1, TERT, TINF2, RTEL1, ACD, or PARN cause about 60% of individuals with Hoyeraal-Hreidarsson syndrome.

Patient description: We describe 14 years of follow-up of an individual with Hoyeraal-Hreidarsson syndrome who initially presented as an infant with intrauterine growth retardation, microcephaly, and central nervous system calcifications. He was diagnosed with Hoyeraal-Hreidarsson syndrome at age 6 years and had a complicated medical history including severe developmental delay, cerebellar hypoplasia, esophageal and urethral stenosis, hip avascular necrosis, immunodeficiency, and bone marrow failure evolving to myelodysplastic syndrome requiring hematopoietic cell transplantation at age 14 years. He had progressive skin pigmentation, oral leukoplakia, and nail dysplasia leading to anonychia. Whole exome sequencing identified novel biallelic variants in PARN.

Conclusions: This patient illustrates that the constellation of intrauterine growth retardation, central nervous system calcifications, and cerebellar hypoplasia, esophageal or urethral stenosis, and cytopenias, in the absence of congenital infection, may be due to Hoyeraal-Hreidarsson syndrome. Early diagnosis of Hoyeraal-Hreidarsson syndrome is important to optimize medical management and provide genetic counseling.

Keywords: CNS calcification; Hoyeraal-Hreidarsson syndrome; PARN; dyskeratosis congenita; microcephaly; telomere.

Publication types

  • Case Reports
  • Research Support, N.I.H., Intramural

MeSH terms

  • DNA Mutational Analysis
  • Dyskeratosis Congenita / diagnostic imaging
  • Dyskeratosis Congenita / genetics*
  • Dyskeratosis Congenita / pathology
  • Dyskeratosis Congenita / therapy
  • Exome
  • Exoribonucleases / genetics*
  • Fetal Growth Retardation / diagnostic imaging
  • Fetal Growth Retardation / genetics*
  • Fetal Growth Retardation / pathology
  • Fetal Growth Retardation / therapy
  • Humans
  • Intellectual Disability / diagnostic imaging
  • Intellectual Disability / genetics*
  • Intellectual Disability / pathology
  • Intellectual Disability / therapy
  • Longitudinal Studies
  • Male
  • Microcephaly / diagnostic imaging
  • Microcephaly / genetics*
  • Microcephaly / pathology
  • Microcephaly / therapy
  • Mutation / genetics*
  • Young Adult


  • Exoribonucleases
  • poly(A)-specific ribonuclease

Supplementary concepts

  • Hoyeraal Hreidarsson syndrome