HPS6 gene

Overview

Gene (OMIM No.)
Function of gene/protein
  • Protein: Subunit 3 of Biogenesis of lysosomal organelles complex 2 (BLOC-2)
  • Forms the BLOC-2 complex with HPS3 and HPS5
  • BLOC-2 complex plays a role in the biogenesis of lysosomes and lysosome-related organelles (LROs)
  • Lysosomes are cytoplasmic organelles that serve as a major degradative compartment in eukaryotes
  • LROs have similar features to lysosomes but have distinct morphology, composition and/or function
  • BLOC-2 controls the sorting and transport of proteins into LROs such as melanosomes and platelet dense granules during their formation
Clinical phenotype
(OMIM phenotype no.)
  • Hermansky-Pudlak syndrome 6 (#614075)
Inheritance
  • Autosomal recessive
Ocular features
  • Albinism
  • Intra- and interfamilial variability in disease severity
Systemic features
  • Skin and hair depigmentation
  • Bleeding diathesis due to platelet storage pool deficiency (easy/prolonged bleeding, easy bruising, prolonged/heavy menorrhagia, epistaxis)
Key investigations
  • Orthoptic assessment and refraction
  • OCT to detect foveal hypoplasia
  • Visual evoked potentials to detect evidence of chiasmal misrouting
  • Eye movement recordings
  • Systemic assessment with a pediatrician, haematologists and other relevant specialists
Molecular diagnosisNext generation sequencing
  • Targeted gene panels (albinism)
  • Whole exome sequencing
  • Whole genome sequencing
ManagementOcularSystemic
  • Multidisciplinary approach
Therapies under research
  • None in clinical trials at present
Further information

Jump to top


References

  1.  Zhang Q, Zhao B, Li W, et al. Ru2 and Ru encode mouse orthologs of the genes mutated in human Hermansky-Pudlak syndrome types 5 and 6. Nat Genet. 2003;33(2):145-153
  2.  Schreyer-Shafir N, Huizing M, Anikster Y, et al. A new genetic isolate with a unique phenotype of syndromic oculocutaneous albinism: clinical, molecular, and cellular characteristics. Hum Mutat. 2006;27(11):1158
  3.  Huizing M, Pederson B, Hess RA, et al. Clinical and cellular characterisation of Hermansky-Pudlak syndrome type 6. J Med Genet. 2009;46(12):803-810
  4.  Miyamichi D, Asahina M, Nakajima J, et al. Novel HPS6 mutations identified by whole-exome sequencing in two Japanese sisters with suspected ocular albinism. J Hum Genet. 2016;61(9):839-842

Jump to top

Updated on November 30, 2020

Was this article helpful?