A prevalent MOCS2 variant in the Roma population is associated with a novel mild form of molybdenum cofactor deficiency

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00023728%3A_____%2F25%3AN0000001" target="_blank" >RIV/00023728:_____/25:N0000001 - isvavai.cz</a>

Alternative codes found

RIV/00023728:_____/25:N0000002 RIV/00216208:11110/25:10500164 RIV/00064165:_____/25:10500164

Result on the web

<a href="https://doi.org/10.1007/s00431-025-06335-x" target="_blank" >https://doi.org/10.1007/s00431-025-06335-x</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00431-025-06335-x" target="_blank" >10.1007/s00431-025-06335-x</a>

Result language

angličtina

Original language name

A prevalent MOCS2 variant in the Roma population is associated with a novel mild form of molybdenum cofactor deficiency

Original language description

Xanthinurias are rare inherited disorders of purine metabolism. Xanthinuria type III is caused by molybdenum cofactor deficiency (MoCD) due to pathogenic variants in MOCS1, MOCS2, MOCS3, or GEPH genes. Here, we described five Roma patients from four unrelated families with hypouricemia, accumulation of xanthine/hypoxanthine, deficiency of xanthine oxidase activity, variable age of diagnosis, and only asymptomatic or mild clinical course. Whole exome sequencing was performed on all probands, aged 3 to 43 years, due to lack of genetic confirmation for xanthinuria types I and II. The causality of the putative pathogenic variant was confirmed by analysis of sulfite and related metabolites and in vitro functional characterization of metal-binding pterin (MPT) synthesis and protein complex formation. Considering the rarity of the condition and recessive inheritance, 34 candidate variants were identified after filtering out allele frequency threshold in non-Finnish Europeans. An ultra-rare MOCS2 variant rs776441627 in two overlapping reading frames (c.244A > T (NM_176806.4; p.Ile82Phe) = c.57A > T (NM_004531.5; p.Leu19Phe)) segregated with the disease in all five patients (four homozygotes, one compound heterozygote). The variant has an allele frequency of 3.6% in a Roma population control group. Functional characterization revealed the significantly decreased MPT synthesis activity and confirmed the causality of rs776441627 in MoCD.  The rs776441627 is a functional variant for MoCD with a mild to asymptomatic clinical phenotype and fully penetrant biochemical phenotype. Hypouricemia should be considered in the differential diagnostic algorithm of pediatric and adult patients with neurological symptoms, and MOCS2 should be considered in gene panels for xanthinuria screening.  Xanthinuria type III is caused by molybdenum cofactor deficiency (MoCD) due to pathogenic variants in MOCS1, MOCS2, MOCS3, or GEPH genes. • The majority of patients with xanthinuria III present with classical early-onset MoCD due to autosomal recessive variants in the MOCS1 gene, manifesting severe progressive neurological complications during the first postnatal days. • To date, approximately 40 patients with MoCD due to pathogenic MOCS2 variants have been reported; most were diagnosed during the neonatal period with intractable seizures and feeding disorders.  A novel ultra-rare variant, rs776441627, located in two overlapping reading frames of the MOCS2, was identified in five Roma patients presenting a mild to asymptomatic clinical MoCD phenotype and a fully penetrant biochemical phenotype. • Functional studies of p.Ile82Phe (small MOCS2A subunit) and p.Leu19Phe (large MOCS2B subunit) demonstrate a strong reduction in molydopterin synthase complex formation and activity, consistent with the changes in biomarkers of MoCD observed in affected individuals. • The rs776441627 variant shows significantly elevated frequency among the Roma population, highlighting the importance of considering ethnic background in the differential diagnosis of MoCD. • Hypouricemia may provide an initial, generally available biochemical key marker indicator of molybdenum cofactor deficiency.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

30209 - Paediatrics

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

EUROPEAN JOURNAL OF PEDIATRICS

ISSN

0340-6199

e-ISSN

1432-1076

Volume of the periodical

184

Issue of the periodical within the volume

Art. Nr. 499

Country of publishing house

DE - GERMANY

Number of pages

13

Pages from-to

1-13

UT code for WoS article

001536395200002

EID of the result in the Scopus database

2-s2.0-105011340431