Albinism & Hermansky–Pudlak syndrome

Last update: November 30, 2018

Recommended panel testing at Breda Genetics for this condition:

Albinism & Hermansky-Pudlak syndrome (AP3B1, BLOC1S3, BLOC1S6, C10ORF11, DTNBP1, GPR143, HPS1, HPS3, HPS4, HPS5, HPS6, LYST, MC1R, MLPH, MITF, MYO5A, OCA2, RAB27A, SLC45A2, TYR, TYRP1)

What is the skin and hair color like?

Oculocutaneous albinism is characterized by hypopigmentation of the skin and hair (including brows and lashes) and distinctive ocular changes including nystagmus and reduced iris pigment with iris translucency. Skin manifestations are minor in X-linked oculocutaenous albinism.

Hermansky–Pudlak syndrome is a rare autosomal recessive disorder which results in oculocutaneous albinism, bleeding diathesis due to a platelet storage pool defect, and lysosomal accumulation of ceroid lipofuscin. In some cases there are pulmonary fibrosis, granulomatous colitis, or immunodeficiency. Hair color ranges from white to brown; skin color ranges from white to olive and is usually a shade lighter than that of other family members.

Sequencing or deletion/duplication testing?

Six genes are known for oculocutaneous albinism: TYR, OCA2, TYRP1, SLC45A2, C10ORF11, and GPR143 genes. Sequencing of the coding region and the exon/intron boundaries is recommended for all genes. Large deletions/duplication testing is also recommended for TYR, OCA2 (the common 2.7 kb deletion is found in most individuals of sub-Saharan African heritage), and GPR143.

Nine genes are known to date to be associated with Hermansky–Pudlak syndrome: HPS1, AP3B1, HPS3, HPS4, HPS5, HPS6, DTNBP1, BLOC1S3, and BLOC1S6. For all them it is recommended to sequence the entire coding region and the exon/intron buondaries. For HPS1, AP3B1, HPS3, HPS6 and BLOC1S6 also deletion/duplication testing is recommended (although the prevalence of such mutation is low).

Which extra genes can be tested?

Disorders with albinism or platelet dense bodies defect included in the differential diagnosis:

– Tietz albinism-deafness syndrome: MITF gene

– Chediak-Higashi syndrome: LYST gene

– Griscelli syndrome 1, 2, and 3: MYO5A, RAB27A, and MLPH genes

– Cross syndrome: no known gene yet

Recommended panel testing at Breda Genetics for this condition:

Albinism & Hermansky-Pudlak syndrome (AP3B1, BLOC1S3, BLOC1S6, C10ORF11, DTNBP1, GPR143, HPS1, HPS3, HPS4, HPS5, HPS6, LYST, MC1R, MLPH, MITF, MYO5A, OCA2, RAB27A, SLC45A2, TYR, TYRP1)

References:

Albinism. Federico JR, Krishnamurthy K. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2018 Jan- 2018 Oct 27. PMID: 30085560

Mutational analysis of oculocutaneous albinism: a compact review. Kamaraj B, Purohit R. Biomed Res Int. 2014;2014:905472. PMID: 25093188

Oculocutaneous albinism. Grønskov K, Ek J, Brondum-Nielsen K. Orphanet J Rare Dis. 2007 Nov 2;2:43. PMID: 17980020

Hermansky-Pudlak Syndrome. El-Chemaly S, Young LR. Clin Chest Med. 2016 Sep;37(3):505-11. PMID: 27514596

Hermansky-Pudlak syndrome: Report of two patients with updated genetic classification and management recommendations. Loredana Asztalos M, Schafernak KT, Gray J, Berry A, Paller AS, Mancini AJ. Pediatr Dermatol. 2017 Nov;34(6):638-646. PMID: 29044644

Griscelli syndrome: a model system to study vesicular trafficking. Van Gele M, Dynoodt P, Lambert J. Pigment Cell Melanoma Res. 2009 Jun;22(3):268-82. PMID: 19243575

Chediak-Higashi syndrome presenting in accelerated phase: A case report and literature review. Maaloul I, Talmoudi J, Chabchoub I, Ayadi L, Kamoun TH, Boudawara T, Kallel CH, Hachicha M. Hematol Oncol Stem Cell Ther. 2016 Jun;9(2):71-5. PMID: 26254864

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