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An Australian family with macular dystrophy linked to autosomal recessive alopecia universalis
  1. LYNDON DA CRUZ,
  2. I L McALLISTER
  1. Lions Eye Institute, 2 Verdun Street
  2. Nedlands, 6009, Western Australia
  1. Dr Lyndon da Cruz, c/o Professor Bird's secretary, Medical Retina Unit, Moorfields Eye Hospital, City Road, London EC1 2PV, UK

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Editor,—A strong linkage between autosomal recessive alopecia universalis and macular dystrophy has not been described before. Recently, the gene for this form of alopecia, the human hairless gene, has been identified at chromosome 8p12-22. There are currently no retinal or macular associated genes which have been described at this locus.

CASE REPORT

A 28 year old landscape gardener presented to the Lions Eye Institute, Perth, with visual problems and a request for assessment. On examination, it was noted that she had marked bilateral, symmetrical, atrophic maculae (Fig 1). In addition, she had marked hair thinning and loss involving the entire head. Her best corrected visual acuity was recorded as 6/36 in both eyes, with the right eye improving to 6/12 with pinhole. She wore a spectacle correction of −4.00 sphere right and −3.50 sphere left.

Figure 1

Clinical photograph (A) and (B) showing the patient's alopecia. Fundus photographs (C) and (D) of the patient, and (E) and (F) of the patient's brother.

Her past history noted hair loss but not symptomatic visual loss as a child. She was seen recurrently at the Royal Children's Hospital, Melbourne, for alopecia and fitting of wigs but not for vision loss. She complained of changing vision affecting reading and other activities in her teens. The visual loss had progressed through her teens and had become a significant disability to function. She did not complain of night blindness.

The patient also described her brother in Melbourne and a cousin in Berlin both of whom had the combination of vision loss and alopecia. The relationship between affected individuals is shown in Figure 2. None of the clinical features described in the affected children were present in the parents or the grandparents. Although neither of the parents of the affected children, nor the grandparents, were consanguineous, they all came from the same small town, Kostajnica, in a hilly region of Croatia. The presence of a likely small gene pool in the region where all the members of the pedigree were from would be consistent with a recessive disease.

Figure 2

Pedigree. The family of the affected individual (P1) with the other affected individuals in black.

Electrophysiological tests were carried out with a normal EOG and normal peak to trough ratios. The scotopic and photopic flash ERG results were reported as unreliable but the tests were not repeated. The pattern ERG was abnormal in the right eye and grossly abnormal in the left with no identifiable components. Flicker ERG responses were at the extreme lower limit of normal in the right and abnormal in the left eye with reduced b-waves.

Other tests showed a total error score on the Farnswoth 100 hue test of 136 right, and 176 left. Goldmann visual fields showed a right central scotoma of about 10 degrees to the stimulus but sparing the superonasal quadrant to the fixation point. The margin of the spared area did not respect the vertical or horizontal meridians. A central scotoma of 10 degrees to the stimulus was seen in the left with no areas spared.

COMMENT

The identification of new, macular related, and disease related genes is sometimes helped by strong linkage to a second disease or marker trait. The strong association of alopecia and macular degeneration does not appear in the literature. Recent identification of alopecia associated genes has allowed tentative allocation of clinical disease entities to these genes.1 The patient described here has the clinical diagnosis of autosomal recessive alopecia universalis. This condition has recently been identified to be associated with mutations in the human hairless gene on chromosome 8p12-22 in some families.1 Expression of this gene has been shown to occur in the brain and because of the origin and nature of the retina would make this a plausible candidate.2There are currently no reported macular diseases associated genes that are present at this locus. Two chromosome-8 related retinal genes have been identified. These are a gene encoding a new oxygen regulated photoreceptor protein causing autosomal dominant retinitis pigmentosa,3 linked to 8q11-13 and a “macular hypoplasia with ERG suggestion of gross abnormality of cone function” in a case of trisomy 8 mosaic syndrome.4

The primary aim of this case study is to report a family that has a strong linkage of congenital alopecia and macular degeneration. Given the recent identification of the gene responsible for autosomal recessive alopecia universalis this may suggest the site of a, currently unknown, gene associated with retinal dystrophy.

References

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