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Hermansky-Pudlak Syndrome Type 9 (HPS9) via the BLOC1S6/PLDN Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
BLOC1S6 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8749BLOC1S681479 81479,81479 $990 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing platform).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing platform).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

Turnaround Time

3 weeks on average for standard orders or 2 weeks on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.


Genetic Counselors


  • Siwu Peng, PhD

Clinical Features and Genetics

Clinical Features

Hermansky-Pudlak Syndrome (HPS) is characterized by tyrosinase-positive oculocutaneous albinism, bleeding diathesis, and significant reduction in visual acuity often characterized by nystagmus, reduced retinal and iris pigmentation, and foveal hypoplasia (Hermansky and Pudlak 1959). Hair and skin color are typically shades lighter than is seen in unaffected relatives. HPS patients may experience frequent epistaxis, easy bruising, and prolonged bleeding with injury or surgery. HPS patients may also develop immunodeficiencies, granulomatous colitis, with onset usually in their teens, and/or pulmonary fibrosis, with onset typically in their thirties or forties (Huizing et al. 2008; Gahl et al. 1998). Similar characteristics are found with the related Chediak-Higashi Syndrome (CHS). HPS and CHS are disorders of storage granules, e.g. melanosomes, platelet-dense granules, lysosomes, and lytic granules. A hallmark of HPS is a lack of platelet dense granules, as seen on electron micrographs (Witkop et al. 1987). CHS is distinguished by giant azurophilic granules in neutrophils, eosinophils, and other granulocytes (Introne et al. 1999).


HPS is a genetically heterogeneous autosomal recessive disorder associated with the HPS1, AP3B1/(HPS2), HPS3, HPS4, HPS5, HPS6, DTNBP1/(HPS7), BLOC1S3/(HPS8), and BLOC1S6(HPS9) genes. HPS proteins belong to the BLOC (Biogenesis of Lysosome-related Organelle Complexes) groups of proteins that function during formation and/or trafficking of lysosme-related vesicles (Huizing et al. 2008). HPS is unusually common in Puerto Rico where regions of the country have an estimated carrier frequency as high as 1 in 21 (Wildenberg et al. 1995). Most affected Puerto Ricans harbor either a 16bp duplication in HPS1 or a 3.9kb deletion in HPS3 (Anikster et al. 2001; Santiago et al. 2006). In non-Puerto Ricans, HPS1 mutations account for ~50% of cases (Oh et al. 1998) with the remaining cases being distributed as follows: AP3B1/(HPS2) ~1%, HPS3 ~13%, HPS4 ~12%, HPS5 ~9%, HPS6 ~7%, DTNBP1/(HPS7) ~1%, BLOC1S3/(HPS8) ~1%, BLOC1S6(HPS9) only two patients to date, homozygous for the c.232 C>T (Gln78Term) pathogenic variant in the BLOC1S6 / HPS9 / PLDN gene, have been reported to date (Cullinane et al. 2011; Badolato et al. 2012).

The severity of HPS varies among the subtypes and among family members having the same subtype, but some general genotype / phenotype correlations have emerged. Patients with HPS1 or HPS4 generally have more severe forms of HPS with more pronounced albinism, development of colitis (Hussain et al. 2006), a high occurrence of pulmonary fibrosis (Huizing et al. 2008), and accelerated ceroid lipfusin accumulation in lung, liver, bone marrow, kidney, and other cells (Huizing and Gahl 2002). The remaining subtypes are generally not associated with pulmonary fibrosis (Huizing et al. 2004), however, HPS2 and HPS9 have been associated with immunodeficiencies (Huizing et al. 2002; Badolato et al. 2012).

Clinical Sensitivity - Sequencing with CNV PGxome

Pathogenic variants in the BLOC1S6 / PLDN gene have been reported in only two patients to date (Cullinane et al. 2011; Badolato et al. 612012).

Testing Strategy

This test provides full coverage of all coding exons of the BLOC1S6 gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).

Indications for Test

Patients with symptoms or family history of HPS, CHS, or Griscelli Syndrome, patients with any degree of hypopigmentation and bleeding diathesis, and patients with morphologically abnormal granulocytes or platelets. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in BLOC1S6.


Official Gene Symbol OMIM ID
BLOC1S6 604310
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Hermansky-Pudlak Syndrome 9 AR 614171

Related Test

Familial Hemophagocytic Lymphohistiocytosis (FHL) Panel


  • Anikster et al. 2001. PubMed ID: 11455388
  • Badolato et al. 2012. PubMed ID: 22461475
  • Cullinane AR, Curry JA, Carmona-Rivera C, Summers CG, Ciccone C, Cardillo ND, Dorward H, Hess RA, White JG, Adams D, Huizing M, Gahl WA. 2011. A BLOC-1 Mutation Screen Reveals that PLDN Is Mutated in Hermansky-Pudlak Syndrome Type 9. Am J Hum Genet 88: 778787. PubMed ID: 21665000
  • Gahl et al. 1998. PubMed ID: 9562579
  • Hermansky and Pudlak. 1959. PubMed ID: 13618373
  • Huizing and Gahl. 2002. PubMed ID: 12125811
  • Huizing et al. 2002. PubMed ID: 11809908
  • Huizing et al. 2004. PubMed ID: 15296495
  • Huizing et al. 2008. PubMed ID: 18544035
  • Hussain et al. 2006. PubMed ID: 16431308
  • Introne et al. 1999. PubMed ID: 10527680
  • Oh et al. 1998. PubMed ID: 9497254
  • Santiago Borrero et al. 2006. PubMed ID: 16417222
  • Wildenberg et al. 1995. PubMed ID: 7573033
  • Witkop et al. 1987. PubMed ID: 3120578


Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page

If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.

Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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Note: acceptable specimen types are whole blood and DNA from whole blood only.
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