Creatine transporter deficiency: Novel mutations and functional studies

X-linked cerebral creatine deficiency (MIM 300036) is caused by deficiency of the creatine transporter encoded by the SLC6A8 gene. Here we report three patients with this condition from Israel. These unrelated patients were evaluated for global developmental delays and language apraxia. Borderline microcephaly was noted in one of them. Diagnosis was prompted by brain magnetic resonance imaging and spectroscopy which revealed normal white matter distribution, but absence of the creatine peak in all three patients. Biochemical testing indicated normal plasma levels of creatine and guanidinoacetate, but an increased urine creatine/creatinine ratio. The diagnosis was confirmed by demonstrating absent ([14])C-creatine transport in fibroblasts. Molecular studies indicated that the first patient is hemizygous for a single nucleotide change substituting a single amino acid (c.619 C > T, p.R207W). Expression studies in HeLa cells confirmed the causative role of the R207W substitution. The second patient had a three base pair deletion in the SLC6A8 gene (c.1222_1224delTTC, p.F408del) as well as a single base change (c.1254 + 1G > A) at a splicing site in the intron-exon junction of exon 8, the latter occurring de novo. The third patient, had a three base pair deletion (c.1006_1008delAAC, p.N336del) previously reported in other patients with creatine transporter deficiency. These three patients are the first reported cases of creatine transporter deficiency in Israel.

Prevention of urethral strictures following coronary artery bypass graft surgery

A total of 62 patients undergoing coronary artery bypass graft surgery were randomized into three groups using one of three methods for bladder drainage: 12F Foley catheter introduced after anesthesia prior to surgery (21 patients); 12F Foley catheter introduced after termination of cardiopulmonary bypass period (17 patients); or a suprapubic catheter, introduced after termination of the bypass period (24 patients). Later we also studied 39 consecutive patients undergoing coronary artery bypass graft surgery with a 12F Foley catheter introduced after anesthesia to assess the risk of urethral stricture in a larger group of patients. The patients' records were reviewed and a postal questionnaire was sent to all patients six months after surgery. The response rate was 84 percent, with 36 percent having complaints about micturition; of these 79 percent were evaluated by cystourethrography, and 2 cases of urethral stricture were found. The incidence of major postoperative complications was low, with no differences in rate among the various groups. Our results indicate that the use of small caliber Foley catheters is associated with a low incidence of urethral strictures following coronary artery bypass graft surgery; and when indicated, this type of surgery can be performed with other methods of bladder drainage without increased morbidity.