Patients with biallelic mutations in the chloride channel gene CLCNKB: long-term management and outcome.
BACKGROUND
Little information on the management and long-term follow-up of patients with biallelic mutations in the chloride channel gene CLCNKB is available.


METHODS
Long-term follow-up was evaluated from 5.0 to 24 years (median, 14 years) after diagnosis in 13 patients with homozygous (n = 10) or compound heterozygous (n = 3) mutations.


RESULTS
Medical treatment at last follow-up control included supplementation with potassium in 12 patients and sodium in 2 patients and medical treatment with indomethacin in 9 patients. At the end of follow-up, body height was 2.0 standard deviation score or less in 6 patients; 2 of these patients had growth hormone deficiency. Body weight (<or=2.0 standard deviation score in 6 patients) significantly increased (P < 0.05) at the end of follow-up in comparison to values at diagnosis. Nonpostural persistent proteinuria was present in 6 patients, and 4 patients had a glomerular filtration rate less than 75 mL/min/1.73 m(2) (<1.25 mL/s).


CONCLUSIONS
These data show that some patients with biallelic mutations in the chloride channel gene CLCNKB tend to present with pathological proteinuria and impaired kidney function after a median follow-up of 14 years, and growth retardation is common and sometimes related to growth hormone deficiency in these patients.
Bettinelli
Alberto
A
Pediatric Renal Unit and Laboratory of Medical Genetics, Fondazione Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, IRCCS. a.bettinelli@ospedale.lecco.it
Borsa
Nicolò
N
Bellantuono
Rosa
R
Syrèn
Marie-Louise
ML
Calabrese
Raffaele
R
Edefonti
Alberto
A
Komninos
John
J
Santostefano
Marisa
M
Beccaria
Luciano
L
Pela
Ivana
I
Bianchetti
Mario G
MG
Tedeschi
Silvana
S
D000293:Adolescent; D000328:Adult; D000483:Alleles; D001477:Bartter Syndrome / Q000188:drug therapy / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D018118:Chloride Channels / Q000235:genetics*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009154:Mutation; D013997:Time Factors
C412733:CLCNKB protein, human; D018118:Chloride Channels