Founder mutations in the ATP6V1B1 gene explain most Cypriot cases of distal renal tubular acidosis: first prenatal diagnosis.
OBJECTIVE
To investigate clinically and genetically all the distal renal tubular acidosis (dRTA) cases in Cyprus, to study one more family from Greece and to perform the first dRTA prenatal diagnosis. We also tried to find any association with sensorineural hearing loss (SNHL) onset and particular mutations.


METHODS
Nine dRTA families from Cyprus and one from Greece were analyzed for mutations in ATP6V1B1 gene by DNA resequencing and PCR-RFLPs. Clinical diagnosis was performed by standard criteria. Prenatal diagnosis was performed for one Cypriot family.


RESULTS
Results show that 7/9 dRTA cases in Cyprus are caused by 229+1G>T and R157C founder mutations in ATP6V1B1 gene. 229+1G>T mutation was estimated to be older than 400 years. No genotype- phenotype correlation was found with SNHL. A known (L81P) and a novel mutation (912delT) were found in the Greek family. Prenatal diagnosis was performed for one Cypriot family, after parents' demand, showing that the embryo was a heterozygous carrier.


CONCLUSIONS
Existence of only two ATP6V1B1 mutations in the Cypriot population is a diagnostic advantage. The age of onset of SNHL varies in our patients and probably is not related to ATP6V1B1 genotypes. Effective therapy for most of the syndrome symptoms is not satisfactory for some parents who choose prenatal diagnosis to ensure their child's health.
Elia
Avraam
A
Department of Pediatric Nephrology, Archbishop Makarios III Hospital, Nicosia, Cyprus.
Voskarides
Konstantinos
K
Demosthenous
Panayiota
P
Michalopoulou
Aikaterini
A
Malliarou
Maria-Adamantia
MA
Georgaki
Eleni
E
Athanasiou
Yiannis
Y
Patsias
Charalambos
C
Pierides
Alkis
A
Deltas
Constantinos
C
D000141:Acidosis, Renal Tubular / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003535:Cyprus / Q000453:epidemiology; D005260:Female; D018703:Founder Effect; D006801:Humans; D007223:Infant; D008297:Male; D009154:Mutation / Q000235:genetics*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis / Q000235:genetics*; D011296:Prenatal Diagnosis / Q000379:methods*; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics*; D055815:Young Adult
C509766:ATP6V1B1 protein, human; D025262:Vacuolar Proton-Translocating ATPases