Quiz

Interactive Quiz: A Child's White Hair and Milky Skin

What's your diagnosis?

Welcome to Consultant360's latest interactive diagnostic quiz. Over the next few pages, we'll present a case and ask you to make the diagnosis. Along the way, we'll provide details about the case, and at the end, we'll share the patient's outcome.

 

Ready to get started?

First, let’s meet the patient.

 

A 3-year-old Chinese girl presented with white hair (Figure 1), white eyelashes, white eyebrows, depigmented skin, and translucent light-blue irides (Figure 2), all of which had been noted at birth. The depigmentation had not improved with time.

 

The girl had been born to a gravida 3, para 2, 30-year-old mother at term following an uncomplicated pregnancy and vaginal delivery. The Apgar score was 7 at 1 minute and 9 at 5 minutes. Her birth weight was 2980 g and length was 49 cm. The neonatal course had been uneventful. Her developmental milestones were normal. She had prominent photophobia. The parents were first-degree cousins and were apparently in good health. Her parents, her 7-year-old brother, and her 5-year-old sister had typical Asian skin complexion, dark hair, and brown irides.

 

On examination, the patient’s scalp hair, eyelashes, and eyebrows were white, and she had milky white skin. Ophthalmologic examination revealed reduced visual acuity, horizontal nystagmus, translucent light-blue irides, foveal hypoplasia, and retinal hypopigmentation. She had no other congenital anomalies, and the rest of the systemic physical examination findings were otherwise normal.

 

 

 

Next page: What’s your diagnosis?

 

See the answer

Answer: C. Oculocutaneous albinism

 

The term albinism is derived from the Latin word albus, meaning white, and refers to the impaired ability of an individual to produce melanin, resulting in hypopigmentation compared with others of the same racial and ethnic background.1,2 The condition was first described scientifically by Sir Archibald Garrod in 1908.3 Clinically, albinism is classified as either oculocutaneous albinism (OCA) or ocular albinism.4 OCA is a group of inherited disorders of impaired melanin synthesis characterized by congenital hypopigmentation of cutaneous and ocular tissues. Seven types of OCA (numbered 1 through 7) caused by mutations in different genes involved in melanin synthesis have been described.5,6 The clinical spectrum of OCA ranges from a generalized complete to partial loss in pigmentation of the skin, hair, and ocular tissues.7 OCA1 is the most severe type of OCA and is characterized by milky white skin, white hair, and light blue or pink and translucent irides at birth, as illustrated in the present case.8,9

 

Next page: Prevalence of OCA

 

See the answer

Answer: B, 17,000 to 20,000

 

The overall prevalence of OCA ranges from 1 per 17,000 to 20,000 in the general population.2,7,10-12 The estimated prevalence of OCA1 is 1 per 40,000 in the general population.2,13 OCA1 is the most frequent type of OCA, accounting for approximately 42% of all cases, and is the most common type found in the Chinese (70%) and white (50%) populations.7,10,14,15 The sex incidence is equal.14

 

Next page: Diagnosing OCA

 

See the answer

Answer: C. Hair-bulb tyrosinase assay

 

The diagnosis is mainly clinical, based on the history and physical examination findings. A hair-bulb tyrosinase assay may be performed to confirm the diagnosis.9 In this assay, scalp hair bulbs are gently plucked from the patient and incubated with DOPA in a test tube for up to 4 hours.9 In patients with OCA1, the hair bulbs remain white due to a lack of tyrosinase activity. On the other hand, hair bulbs from all other subtypes of OCA demonstrate some degree of pigment production.

 

Visual evoked potential tests may be used to demonstrate the characteristic chiasmatic misrouting of optic nerve fibers in patients with OCA.1,13 Patients with OCA show an asymmetry of visual evoked potential between the 2 eyes secondary to chiasmatic misrouting of the optic nerve fibers.

 

Molecular genetic testing using polymerase chain reaction and DNA sequencing analysis may be necessary to establish the gene defect of different types of OCA due to high level of genetic heterogeneity, lack of genotype-phenotype correction, and overlap of phenotypes between the OCA types.7,13

 

Click here to read the full case report.

 

Next page: References

Quiz adapted from: Leung AKC, Lam JM, Leung AAM. What’s the cause of this girl’s white hair, milky skin, and blue eyes? Consultant. 2018;58(5):e172.

 

Alexander K. C. Leung, MD, is a clinical professor of pediatrics at the University of Calgary and a pediatric consultant at the Alberta Children’s Hospital in Calgary, Alberta, Canada.

 

Joseph M. Lam, MD, is a clinical associate professor in the Department of Pediatrics at the University of British Columbia and an associate member at the Department of Dermatology and Skin Sciences at the University of British Columbia, Vancouver, British Columbia, Canada.

 

Amy A. M. Leung, OD, is a medical student at the University of Alberta, in Edmonton, Alberta, Canada.

 

 

REFERENCES:

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  2. Maia M, Volpini BMF, dos Santos GA, Rujula MJP. Quality of life in patients with oculocutaneous albinism. An Bras Dermatol. 2015;90(4):513-517.
  3. Garrod AE. The Croonian Lectures on inborn errors of metabolism. Lecture II. Lancet. 1908;2:73-79.
  4. Kirkwood BJ. Albinism and its implications with vision. Insight. 2009;34(2):13-16.
  5. Okamura K, Yoshizawa J, Abe Y, et al. Oculocutaneous albinism (OCA) in Japanese patients: five novel mutations. J Dermatol Sci. 2014;74(2):173-174.
  6. Summers CG, Hand JL. Oculocutaneous albinism. UpToDate. https://www.uptodate.com/contents/oculocutaneous-albinism. Updated December 13, 2017. Accessed March 19, 2018.
  7. Lasseaux E, Plaisant C, Michaud V, et al. Molecular characterization of a series of 990 index patients with albinism [published online February 14, 2018]. Pigment Cell Melanoma Res. 2018 Jan 18. doi:10.1111/pcmr.12688
  8. Ghodsinejad Kalahroudi V, Kamalidehghan B, Arasteh Kani A, et al. Two novel tyrosinase (TYR) gene mutations with pathogenic impact on oculocutaneous albinism type 1 (OCA1). PLoS One. 2014;9(9):e106656.
  9. Okulicz JF, Shah RS, Schwartz RA, Janniger CK. Oculocutaneous albinism. J Eur Acad Dermatol Venereol. 2003;17(3):251-256.
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  18. Kromberg JG, Bothwell J, Kidson SH, Manga P, Kerr R, Jenkins T. Types of albinism in the Black Southern Africa population. East Afr Med J. 2012;89(1):20-27.
  19. Kutzbach BR, Summers CG, Holleschau AM, MacDonald JT. Neurodevelopment in children with albinism. Ophthalmology. 2008;115(10):1805-1808.e2.
  20. Scheinfeld NS. Syndromic albinism: a review of genetics and phenotypes. Dermatol Online J. 2003;9(5):5.
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  22. de Vijlder HC, de Vijlder JJM, Neumann HAM. Oculocutaneous albinism and skin cancer risk. J Eur Acad Dermatol Venereol. 2013;27(3):e433-434.
  23. Knöpfel N, Martín-Santiago A, Del Pozo LJ, Saus C, Pascual M, Requena L. Amelanotic naevoid melanoma in a 16-month-old albino infant. Clin Exp Dermatol. 2017;42(1):84-88.
  24. Minakawa S, Kaneko T, Matsuzaki Y, et al. Case of oculocutaneous albinism complicated with squamous cell carcinoma, Bowen’s disease and actinic keratosis. J Dermatol. 2014;41(9):863-864.
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