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ABSTRACT: Background
The Roma are a European ethnic minority threatened by several recessive diseases. Variants in MANBA cause a rare lysosomal storage disorder named beta-mannosidosis whose clinical manifestation includes deafness and mental retardation. Since 1986, only 23 patients with beta-mannosidosis and biallelic MANBA variants have been described worldwide.Results
We now report on further 10 beta-mannosidosis patients of Roma origin from eight families in the Czech and Slovak Republics with hearing loss, mental retardation and homozygous pathogenic variants in MANBA. MANBA variant c.2158-2A>G screening among 345 anonymized normal hearing controls from Roma populations revealed a carrier/heterozygote frequency of 3.77%. This is about 925 times higher than the frequency of this variant in the gnomAD public database and classifies the c.2158-2A>G variant as a prevalent, ethnic-specific variant causing hearing loss and mental retardation in a homozygous state. The frequency of heterozygotes/carriers is similar to another pathogenic variant c.71G>A (p.W24*) in GJB2, regarded as the most frequent variant causing deafness in Roma populations.Conlcusion
Beta-mannosidosis, due to a homozygous c.2158-2A>G MANBA variant, is an important and previously unknown cause of hearing loss and mental retardation among Central European Roma.
SUBMITTER: Safka Brozkova D
PROVIDER: S-EPMC7448337 | biostudies-literature | 2020 Aug
REPOSITORIES: biostudies-literature
Safka Brozkova Dana D Varga Lukas L Uhrova Meszarosova Anna A Slobodova Zuzana Z Skopkova Martina M Soltysova Andrea A Ficek Andrej A Jencik Jan J Lastuvkova Jana J Gasperikova Daniela D Seeman Pavel P
Orphanet journal of rare diseases 20200826 1
<h4>Background</h4>The Roma are a European ethnic minority threatened by several recessive diseases. Variants in MANBA cause a rare lysosomal storage disorder named beta-mannosidosis whose clinical manifestation includes deafness and mental retardation. Since 1986, only 23 patients with beta-mannosidosis and biallelic MANBA variants have been described worldwide.<h4>Results</h4>We now report on further 10 beta-mannosidosis patients of Roma origin from eight families in the Czech and Slovak Repub ...[more]