Chronic Cough and Cerebellar Ataxia With Neuropathy and Bilateral Vestibular Areflexia Syndrome (CANVAS): Screening for Mutations in Replication Factor C Subunit 1 (RFC1).

INTRODUCTION: A common complaint in patients is chronic cough (CC), which may be refractory (RCC) or unexplained (UCC). Recent studies point, as a possible cause of CC, to the hereditary cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome (CANVAS), with an estimated carrier prevalence of 1 in 20000. AIM: In patients with CC, determine the prevalence of the biallelic (AAGGG)exp mutation in replication factor C subunit 1 (RFC1) responsible for CANVAS, test the usefulness of the Rydel-Seiffer fork test, and evaluate patient quality of life (QoL). METHODS: Clinical and functional data were collected for the 33 included patients undergoing CC studies in our specialized unit. Performed were an etiological study of CC following European Respiratory Society recommendations, a genetic study of RFC1 mutations, and Rydel-Seiffer fork testing to detect possible peripheral vibratory sensitivity impairment. Administered to evaluate QoL were 4 questionnaires. RESULTS: Prevalence of biallelic (AAGGG)exp in RFC1 was 6.1% (n=2) overall, increasing to 7.1% in the RCC subgroup, and to 33.3% in the Rydel-Seiffer fork altered results subgroup. Prevalence of monoallelic (AAGGG)exp in RFC1 was 18.2% (n=6) overall, rising to 50.0% (n=2) in the UCC subgroup. CONCLUSION: Genetic screening for (AAGGG)exp in RFC1, and also use of the Rydel-Seiffer fork test, should be considered in specialized CC consultations for patients with RCC and UCC. Detecting possible CANVAS symptoms in CC studies would identify candidates for early genetic screening, of interest in reducing the disease burden for patients and health systems alike.

An update on the molecular analysis of classical galactosaemia patients diagnosed in Spain and Portugal: 7 new mutations in 17 new families

Background and objectives: Classical galactosaemia is an inherited metabolic disorder due to mutations in the galactose-1-phosphate uridytransferase gene (GALT). We previously reported molecular analysis of 83 Spanish and Portuguese unrelated galactosaemic patients. Here we present the results of another seventeen unreported affected individuals. Material and methods: DNA from patients was PCR-amplified and sequenced following standard protocols. Results: Twelve patients diagnosed in Spain were studied. We detected five alleles carrying p.Q188R, accounting for 21%. Other six alleles (25%) were identified with the mutation p.K285N. We also identified six novel mutations: p.Q9X, c.328+2T>C, p.I170N, p.C180F, p.V233L and p.P257L. Taking into account all the Spanish galactosaemic diagnosed patients, mutation p.Q188R is still the most frequent mutation identified (44.4%). In five new Portuguese patients, five alleles p.Q188R were detected, representing 50%. One novel mutation (p.F171C) was identified. Conclusions: Our results confirm our previous observations that p.Q188R is the most frequent mutation in Iberian Peninsula galactosaemic patients (49%), and that Portuguese and Spanish genotypes differ (AU)

Fundamento y objetivo: La galactosemia clásica es una enfermedad metabólica hereditaria debida a mutaciones en el gen de la galactosa-1-fosfato uridiltransferasa (GALT). Nuestro grupo ya publicó los resultados del análisis molecular de 83 pacientes galactosémicos de España y Portugal. Aquí se presentan los resultados de una nueva serie de pacientes. Material y método: El ADN de los 17 pacientes estudiados se amplificó por PCR y se secuenció siguiendo métodos ya descritos. Resultados: Se analizó a 12 doce pacientes diagnosticados en España y detectamos 5 alelos con la mutación p.Q188R (21%). Otros 6 alelos (25%) resultaron portadores de la mutación p.K285N. También se identificaron 6 mutaciones nuevas:p.Q9X,c.328+2T4C, p.I170N, p.C180F, p.V233L y p.P257L. Considerando a todos los pacientes diagnosticados en España, la mutación p.Q188R sigue siendo la mutación mas frecuente (44,4%). En 5 pacientes portugueses se detectaron 5 alelosp.Q188R(50%) y se identificó una nueva mutación (p.F171C). Conclusiones: Estos resultados confirman las observaciones previas, en las cuales se mostraba que la mutación más frecuente en la península Ibérica es p.Q188R(49%), pero que los genotipos españoles y portugueses difieren entre sí (AU)