Dysfunctional Voiding of Non-Neurogenic Neurogenic Bladder: A Urological Disorder Associated with Down Syndrome

Abstract

Down syndrome (DS), the most common chromosomal abnormality with a prevalence of 1 case per 600 live births (Dennis & Marder,2001), has many manifestations that can affect multiple organ systems (American Academy of Pediatrics Comittee on Genetics, 2001; Kallen et al., 1996) including urological abnormalities which have been recognized throughout urinary tract (Ariel et al., 1991; Berg et al.,1960; Ahmed, 1990; Kravtzova et al., 1975; Handel et al., 2003; Kupferman et al., 1996; Bielek et al., 1996; Narashiman & Gupta, 2004; Koksal et al., 2003; Lang et al., 1987; Paulozzi et al., 1997). The extra copy of chromosome 21 has been suggested as an actor underlying the accompanied phenotypic abnormalities in the syndrome (Lejeune, 1959). Berg et al. described the first cases of urological anomalies associated with DS in their study of 141 DS autopsy cases and found 1 patient (0.7%) with renal agenesis and 5 patients (3.6%) with horseshoe kidney (Berg et al., 1960). Glomerular microcysts, renal hypoplasia and obstructive uropathy have also been recognized as the most common upper urinary tract anomalies in DS and their incidences were reported by Ariel et al. who examined 124 autopsy cases of DS for abnormalities in urinary tract system to be as high as 23.7% (23 of 97 patients), 21.4% (18 of 84 patients), and 6.45% (8 of the 124 cases), respectively (Ariel et al., 1991). In addition, simple renal cysts were also found in 7 of 124 cases (5.6%). Anomalies in ureteral structure has also been identified in DS (Ariel et al., 1991; Kravtzova et al., 1975; Handel et al., 2003). The incidence of obstructed megaureter or hydroureteronephrosis was reported in 2 of 124 cases (1.6%), while ureteral atresia was seen in 1 of 124 cases (0.8%) (Ariel et al., 1991). In addition, vesicoureteral reflux (Kravtzova et al., 1975), ureterovesical junction and ureteropelvic junction obstructions have also been described in patients with trisomy 21 (Handel et al., 2003). Trisomy 21 is one of genetic disorders that can also be accompanied by some urological abnormalities in lower urinary tract. Non-neurogenic neurogenic bladder (NNB) has been reported as a functional lower urinary tract abnormality seen in DS. Handel et al. retrospectively reviewed 26 patients with trisomy 21 and found 4 patients (15.4%) with NNB (Handel et al., 2003). Posterior urethral valve has also been identified in patients with trisomy 21 (Bielek et al., 1996; Narashiman & Gupta, 2004; Koksal et al., 2003; Lang DJ et al., 1987). Bielek et al who reviewed 48 cases of posterior urethral valves found 4 patients with