Fraser syndrome associated with anterior urethral atresia

Lower urinary tract development and disease

Congenital anomalies of the lower urinary tract (CALUT) are a family of birth defects of the ureter, the bladder, and the urethra. CALUT includes ureteral anomaliesc such as congenital abnormalities of the ureteropelvic junction (UPJ) and ureterovesical junction (UVJ), and birth defects of the bladder and the urethra such as bladder-exstrophy-epispadias complex (BEEC), prune belly syndrome (PBS), and posterior urethral valves (PUVs). CALUT is one of the most common birth defects and is often associated with antenatal hydronephrosis, vesicoureteral reflux (VUR), urinary tract obstruction, urinary tract infections (UTI), chronic kidney disease, and renal failure in children. Here, we discuss the current genetic and molecular knowledge about lower urinary tract development and genetic basis of CALUT in both human and mouse models. We provide an overview of the developmental processes leading to the formation of the ureter, the bladder, and the urethra, and different genes and signaling pathways controlling these developmental processes. Human genetic disorders that affect the ureter, the bladder and the urethra and associated gene mutations are also presented. As we are entering the postgenomic era of personalized medicine, information in this article may provide useful interpretation for the genetic and genomic test results collected from patients with lower urinary tract birth defects. With evidence-based interpretations, clinicians may provide more effective personalized therapies to patients and genetic counseling for their families.

Fraser syndrome and cryptophthalmos: review of the diagnostic criteria and evidence for phenotypic modules in complex malformation syndromes

Fraser syndrome is characterised by cryptophthalmos, cutaneous syndactyly, malformations of the larynx and genitourinary tract, craniofacial dysmorphism, orofacial clefting, mental retardation, and musculoskeletal anomalies. The inheritance is autosomal recessive. No diagnostic cytogenetic abnormalities have been documented in affected patients, and no molecular genetic studies have been reported. We have reviewed 117 cases diagnosed as Fraser syndrome or cryptophthalmos published since the comprehensive review of Thomas et al in 1986 in order to validate the published diagnostic criteria and to delineate the phenotype associated with this syndrome. Our series showed more females (57/117) than males and consanguinity was present in 29/119 (24.8%). Eighty-eight patients satisfied the diagnostic criteria for Fraser syndrome (75%). Cryptophthalmos was present in 103/117 (88%), syndactyly in 72/117 (61.5%), and ambiguous genitalia in 20/117 (17.1%). Ear malformations were recorded in 69/117 (59%), and renal agenesis in 53/117 (45.3%). Use of the published diagnostic criteria excluded several patients with cryptophthalmos and one or more physical feature(s) consistent with Fraser syndrome. The frequency of additional anomalies in our series was also higher than previously reported (for example, imperforate anus or anal stenosis were found in 34/117 (29%) compared with 2/124 (2%) in the series of Thomas et al (1986) and choanal stenosis or atresia was present in 7/117 (6%) compared to 0/124. These findings emphasise the clinical variability associated with Fraser syndrome and support genetic heterogeneity of the syndrome. We also noted patterns of anomalies (for example, bicornuate uterus with imperforate anus or anal stenosis and renal malformations) that are found in other syndromes and associations without cryptophthalmos, suggesting that common modifier genes may explain some of the phenotypic variation in Fraser syndrome.