eMedicine Specialties > Ophthalmology > Genetic Disorders

Albinism: Differential Diagnoses & Workup

Author: Mounir Bashour, MD, CM, FRCS(C), PhD, FACS, Assistant Professor of Ophthalmology, McGill University; Clinical Assistant Professor of Ophthalmology, Sherbrooke University; Medical Director, Cornea Laser and Lasik MD
Coauthor(s): Khalid Hasanee, MD, Glaucoma and Anterior Segment Fellow, Department of Ophthalmology, University of Toronto; Iqbal Ike K Ahmed, MD, FRCSC, Clinical Assistant Professor, Department of Ophthalmology, University of Utah
Contributor Information and Disclosures

Updated: Sep 10, 2007

Differential Diagnoses

Hermansky-Pudlak Syndrome
Ichthyosis

Other Problems to Be Considered

Chediak-Higashi syndrome
Congenital motor nystagmus
Kallmann syndrome
X-linked ichthyosis
Waardenburg syndrome
Microphthalmia with linear skin defects

Workup

Laboratory Studies

  • Hair bulb assays help to indicate the status of tyrosinase activity. Hair bulbs are taken from the scalp, and the catalytic activity of tyrosinase is determined either by incubation in DOPA and the consequential induction of melanin determined by visual inspection or by a radioactive biochemical assay in which the samples are incubated with a radiolabeled tyrosine precursor and the amount of radiolabel released after enzymatic conversion quantified spectrophotometrically. The usefulness of this test is debatable since a negative result indicates OCA 1A, but a positive result still leaves the possibility of OCA 1, OCA 2, OCA 3, or OA 1.
  • The most definitive test in determining the albinism type is genetic sequence analysis. Of course, the test is useful only for families with individuals who have albinism. The test cannot be used as a screening tool.
  • Genetic sequence analysis can be used to determine if a fetus has albinism. Amniocentesis at 16-18 weeks could be performed to obtain a sample for analysis. However, parents should be aware that children with albinism could function well and have a good prognosis.
  • Obtain a bleeding time if the patient is planning to undergo surgery. Some physicians believe that a bleeding time should be obtained in all albinos. If HPS is suspected, bleeding time, platelet aggregation, and platelet electron microscopy is necessary.
  • If CHS is suspected, a hematologist should evaluate polymorphonuclear leukocyte function.

Other Tests

Visual-evoked potential (VEP) tests

  • Sweep VEP testing can be used as a predictive tool for recognition acuity in children with albinism. Predictability was found in a clinical spectrum of albinism.4
  • Pattern appearance VEP shows a strong association between the magnitude of the interhemispheric latency asymmetry and the clinical signs of albinism.5
  • Flash VEP also shows a strong association between the magnitude of the interhemispheric latency asymmetry and the clinical signs of albinism.5

Histologic Findings

Histologic examination of the skin of male patients with this condition and female carriers of OA 1 reveals the presence of macromelanosomes.

More on Albinism

Overview: Albinism
Differential Diagnoses & Workup: Albinism
Treatment & Medication: Albinism
Follow-up: Albinism
References
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References

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  2. Innamorati G, Piccirillo R, Bagnato P, Palmisano I, Schiaffino MV. The melanosomal/lysosomal protein OA1 has properties of a G protein-coupled receptor. Pigment Cell Res. Apr 2006;19(2):125-35. [Medline].

  3. Brodsky MC, Fray KJ. Positive angle kappa: a sign of albinism in patients with congenital nystagmus. Am J Ophthalmol. Apr 2004;137(4):625-9. [Medline].

  4. Bradfield YS, France TD, Verhoeve J, Gangnon RE. Sweep visual evoked potential testing as a predictor of recognition acuity in albinism. Arch Ophthalmol. May 2007;125(5):628-33. [Medline].

  5. Dorey SE, Neveu MM, Burton LC, Sloper JJ, Holder GE. The clinical features of albinism and their correlation with visual evoked potentials. Br J Ophthalmol. Jun 2003;87(6):767-72. [Medline].

  6. Carden SM, Boissy RE, Schoettker PJ, Good WV. Albinism: modern molecular diagnosis. Br J Ophthalmol. Feb 1998;82(2):189-95. [Medline].

  7. Charles SJ, Green JS, Grant JW, Yates JR, Moore AT. Clinical features of affected males with X linked ocular albinism. Br J Ophthalmol. Apr 1993;77(4):222-7. [Medline].

  8. Creel D, Witkop CJ Jr, King RA. Asymmetric visually evoked potentials in human albinos: evidence for visual system anomalies. Invest Ophthalmol. Jun 1974;13(6):430-40. [Medline].

  9. Cullom RD, Chang B. Albinism. In: Wills Eye Manual: Office & Emergency Room Diagnosis & Treatment of Eye Disease. 2nd ed. Lippincott Williams & Wilkins: 1994:408-409.

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  11. Giebel LB, Tripathi RK, Strunk KM, Hanifin JM, Jackson CE, King RA, et al. Tyrosinase gene mutations associated with type IB ("yellow") oculocutaneous albinism. Am J Hum Genet. Jun 1991;48(6):1159-67. [Medline].

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  13. King RA, Hearing VJ, Creed DJ, Oetting WS. The Metabolic and Molecular Bases of Inherited Disease. 7th ed. McGraw-Hill; 1995:4353-92.

  14. King RA, Pietsch J, Fryer JP, Savage S, Brott MJ, Russell-Eggitt I, et al. Tyrosinase gene mutations in oculocutaneous albinism 1 (OCA1): definition of the phenotype. Hum Genet. Nov 2003;113(6):502-13. [Medline].

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  16. King RA, Summers GC, Haefemeyer JW, LeRoy B. Facts About Albinism. [Full Text].

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  18. Oetting WS. The tyrosinase gene and oculocutaneous albinism type 1 (OCA1): A model for understanding the molecular biology of melanin formation. Pigment Cell Res. Oct 2000;13(5):320-5. [Medline].

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  22. Ramsay M, Colman MA, Stevens G, Zwane E, Kromberg J, Farrall M. The tyrosinase-positive oculocutaneous albinism locus maps to chromosome 15q11.2-q12. Am J Hum Genet. Oct 1992;51(4):879-84. [Medline].

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  25. Toyofuku K, Valencia JC, Kushimoto T, Costin GE, Virador VM, Vieira WD, et al. The etiology of oculocutaneous albinism (OCA) type II: the pink protein modulates the processing and transport of tyrosinase. Pigment Cell Res. Jun 2002;15(3):217-24. [Medline].

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  27. Wang T, Waters CT, Jakins T, Yates JR, Trump D, Bradshaw K, et al. Temperature sensitive oculocutaneous albinism associated with missense changes in the tyrosinase gene. Br J Ophthalmol. Oct 2005;89(10):1383-4. [Medline].

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  29. Zahed L, Zahreddine H, Noureddine B, Rebeiz N, Shakar N, Zalloua P. Molecular basis of oculocutaneous albinism type 1 in Lebanese patients. J Hum Genet. 2005;50(6):317-9. [Medline].

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Further Reading

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Keywords

oculocutaneous albinism, ocular albinism, melanin

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Contributor Information and Disclosures

Author

Mounir Bashour, MD, CM, FRCS(C), PhD, FACS, Assistant Professor of Ophthalmology, McGill University; Clinical Assistant Professor of Ophthalmology, Sherbrooke University; Medical Director, Cornea Laser and Lasik MD
Mounir Bashour, MD, CM, FRCS(C), PhD, FACS is a member of the following medical societies: American Academy of Ophthalmology, American Association for Pediatric Ophthalmology and Strabismus, American College of International Physicians, American College of Surgeons, American Medical Association, American Society of Cataract and Refractive Surgery, American Society of Mechanical Engineers, American Society of Ophthalmic Plastic and Reconstructive Surgery, Biomedical Engineering Society, Canadian Medical Association, Canadian Ophthalmological Society, Contact Lens Association of Ophthalmologists, International College of Surgeons US Section, Ontario Medical Association, Quebec Medical Association, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

Coauthor(s)

Khalid Hasanee, MD, Glaucoma and Anterior Segment Fellow, Department of Ophthalmology, University of Toronto
Khalid Hasanee, MD is a member of the following medical societies: Canadian Medical Association, Canadian Ophthalmological Society, and Ontario Medical Association
Disclosure: Nothing to disclose.

Iqbal Ike K Ahmed, MD, FRCSC, Clinical Assistant Professor, Department of Ophthalmology, University of Utah
Iqbal Ike K Ahmed, MD, FRCSC is a member of the following medical societies: American Academy of Ophthalmology, American Society of Cataract and Refractive Surgery, Canadian Ophthalmological Society, and Ontario Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Gerhard W Cibis, MD, Director of Pediatric Ophthalmology Service, Clinical Professor, Clinical Professor, Department of Ophthalmology, Department of Ophthalmology, University of Kansas; Director, Children's Mercy Hospital, University of Missouri at Kansas City
Gerhard W Cibis, MD is a member of the following medical societies: American Academy of Ophthalmology, American Ophthalmological Society, and Association for Research in Vision and Ophthalmology
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

J James Rowsey, MD, Director of Corneal Services, St Luke's Cataract and Laser Institute, Florida
Disclosure: Nothing to disclose.

CME Editor

Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri
Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Hampton Roy Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, and Pan-American Association of Ophthalmology
Disclosure: Nothing to disclose.

 
 
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