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Heterozygous p.Asp50Asn mutation in the GJB2 gene in two Cameroonian patients with keratitis-ichthyosis-deafness (KID) syndrome.

Wonkam A, Noubiap JJ, Bosch J, Dandara C, Toure GB - BMC Med. Genet. (2013)

Bottom Line: The two patients were heterozygous for the most frequent p.Asp50Asn mutation.Our finding has implication in medical genetic practice, specifically in the molecular diagnosis of KID in Africans.These cases also reveal and emphasize the urgent need to develop appropriate policies to care for patients with rare/orphan diseases in Sub-Saharan Africa, as many of these cases become more and more recognizable.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Human Genetics, Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. ambroise.wonkam@uct.ac.za

ABSTRACT

Background: Keratitis-Ichthyosis-Deafness (KID) syndrome (OMIM 148210) is a congenital ectodermal defect that consists of an atypical ichthyosiform erythroderma associated with congenital sensorineural deafness. KID appears to be genetically heterogeneous and most cases are caused by GJB2 mutations. Mutations in African patients have been rarely described.

Case presentation: We report on two unrelated Cameroonian individuals affected with sporadic KID, presenting with the classic phenotypic triad. The two patients were heterozygous for the most frequent p.Asp50Asn mutation. This first report in patients from sub-Saharan African origin supports the hypothesis that the occurrence of KID due to p.Asp50Asn mutation in GJB2 seems not to be population specific.

Conclusions: Our finding has implication in medical genetic practice, specifically in the molecular diagnosis of KID in Africans. These cases also reveal and emphasize the urgent need to develop appropriate policies to care for patients with rare/orphan diseases in Sub-Saharan Africa, as many of these cases become more and more recognizable.

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Related in: MedlinePlus

Illustrations of some clinical features of the two Cameroonian KID cases (Case 1; panels A-D; Case 2 panels E and F). A) Keratoderma of the soles B) Rippled hyperkeratotic plaques on the knees; C) Hypotrichosis of the eyelashes and eyebrows; D) Mild vascularizing keratitis; E) Hyperkeratosis of the hands; F) Alopecia, hypotrichosis, ichthyosiform erythrokeratoderma.
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Figure 1: Illustrations of some clinical features of the two Cameroonian KID cases (Case 1; panels A-D; Case 2 panels E and F). A) Keratoderma of the soles B) Rippled hyperkeratotic plaques on the knees; C) Hypotrichosis of the eyelashes and eyebrows; D) Mild vascularizing keratitis; E) Hyperkeratosis of the hands; F) Alopecia, hypotrichosis, ichthyosiform erythrokeratoderma.

Mentions: A five-year-old girl that presented with a profound bilateral sensorineural deafness diagnosed at 2 years old. She was born at term to unrelated healthy parents after an uneventful pregnancy and normal vaginal delivery, and presented at birth with generalized erythema. She had a history of chronic otitis externa and hypohidrosis. Her psychomotor development was normal; however, physical examination revealed a generalized thickened skin and xeroderma, palmoplantar keratoderma and rippled hyperkeratotic plaques on the knees and elbows (Figure 1A-D). She had aged facial appearance, hypotrichosis (sparse of eyelashes and eyebrows), and hyperkeratosis lesions in the external auditory canal. Ophthalmologic examination revealed a mild vascularizing keratitis which explained her photophobia and reduced visual acuity. Oral examination showed dental dysplasia and histopathological examination of the skin revealed an acanthotic dyskeratosis. The parents were non-consanguineous and there was no family history of similar condition.


Heterozygous p.Asp50Asn mutation in the GJB2 gene in two Cameroonian patients with keratitis-ichthyosis-deafness (KID) syndrome.

Wonkam A, Noubiap JJ, Bosch J, Dandara C, Toure GB - BMC Med. Genet. (2013)

Illustrations of some clinical features of the two Cameroonian KID cases (Case 1; panels A-D; Case 2 panels E and F). A) Keratoderma of the soles B) Rippled hyperkeratotic plaques on the knees; C) Hypotrichosis of the eyelashes and eyebrows; D) Mild vascularizing keratitis; E) Hyperkeratosis of the hands; F) Alopecia, hypotrichosis, ichthyosiform erythrokeratoderma.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750395&req=5

Figure 1: Illustrations of some clinical features of the two Cameroonian KID cases (Case 1; panels A-D; Case 2 panels E and F). A) Keratoderma of the soles B) Rippled hyperkeratotic plaques on the knees; C) Hypotrichosis of the eyelashes and eyebrows; D) Mild vascularizing keratitis; E) Hyperkeratosis of the hands; F) Alopecia, hypotrichosis, ichthyosiform erythrokeratoderma.
Mentions: A five-year-old girl that presented with a profound bilateral sensorineural deafness diagnosed at 2 years old. She was born at term to unrelated healthy parents after an uneventful pregnancy and normal vaginal delivery, and presented at birth with generalized erythema. She had a history of chronic otitis externa and hypohidrosis. Her psychomotor development was normal; however, physical examination revealed a generalized thickened skin and xeroderma, palmoplantar keratoderma and rippled hyperkeratotic plaques on the knees and elbows (Figure 1A-D). She had aged facial appearance, hypotrichosis (sparse of eyelashes and eyebrows), and hyperkeratosis lesions in the external auditory canal. Ophthalmologic examination revealed a mild vascularizing keratitis which explained her photophobia and reduced visual acuity. Oral examination showed dental dysplasia and histopathological examination of the skin revealed an acanthotic dyskeratosis. The parents were non-consanguineous and there was no family history of similar condition.

Bottom Line: The two patients were heterozygous for the most frequent p.Asp50Asn mutation.Our finding has implication in medical genetic practice, specifically in the molecular diagnosis of KID in Africans.These cases also reveal and emphasize the urgent need to develop appropriate policies to care for patients with rare/orphan diseases in Sub-Saharan Africa, as many of these cases become more and more recognizable.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Human Genetics, Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. ambroise.wonkam@uct.ac.za

ABSTRACT

Background: Keratitis-Ichthyosis-Deafness (KID) syndrome (OMIM 148210) is a congenital ectodermal defect that consists of an atypical ichthyosiform erythroderma associated with congenital sensorineural deafness. KID appears to be genetically heterogeneous and most cases are caused by GJB2 mutations. Mutations in African patients have been rarely described.

Case presentation: We report on two unrelated Cameroonian individuals affected with sporadic KID, presenting with the classic phenotypic triad. The two patients were heterozygous for the most frequent p.Asp50Asn mutation. This first report in patients from sub-Saharan African origin supports the hypothesis that the occurrence of KID due to p.Asp50Asn mutation in GJB2 seems not to be population specific.

Conclusions: Our finding has implication in medical genetic practice, specifically in the molecular diagnosis of KID in Africans. These cases also reveal and emphasize the urgent need to develop appropriate policies to care for patients with rare/orphan diseases in Sub-Saharan Africa, as many of these cases become more and more recognizable.

Show MeSH
Related in: MedlinePlus