Cryptorchidism, or failure of testicular descent, is a common human congenital abnormality with a multifactorial etiology that likely reflects the involvement of endocrine, environmental, and hereditary factors. Cryptorchidism can result in infertility and increases risk for testicular tumors. Testicular descent from abdomen to scrotum occurs in 2 distinct phases: the transabdominal phase and the inguinoscrotal phase (summary by Gorlov et al., 2002).

Severe distention of the kidney with dilation of the renal pelvis and calices.

The presence of multiple cysts in both kidneys.

The presence of a fistula connecting the urinary bladder to the vagina.

Hydrometrocolpos is an accumulation of uterine and vaginal secretions as well as menstrual blood in the uterus and vagina.

The distention of the ureter with urine.

Congenital occlusion of the vagina or adhesion of the walls of the vagina causing occlusion.

A rare vaginal malformation characterized by the presence of a complete or incomplete transverse septum at any level of the vagina (most frequently the upper or middle third), resulting from incomplete fusion between the Müllerian duct component and the urogenital sinus component of the vagina during embryogenesis. The condition is only rarely diagnosed in neonates or infants, unless it causes significant hydromucocolpos. Complete septa present with primary amenorrhea, cyclic pelvic pain, dyspareunia, or a pelvic mass consisting of accumulated menstrual blood, while incomplete septa may lead to dyspareunia and dysmenorrhea.

Webbing or fusion of the fingers or toes, involving soft parts only or including bone structure. Bony fusions are referred to as "bony" syndactyly if the fusion occurs in a radio-ulnar axis. Fusions of bones of the fingers or toes in a proximo-distal axis are referred to as "symphalangism".

An abnormal accumulation of excess fluid in the lower extremity resulting in swelling of the feet and extending upward to the lower leg.

Supernumerary digits located at the ulnar side of the hand (that is, on the side with the fifth finger).

The presence of a supernumerary finger (not a thumb) involving the third or fourth metacarpal with associated osseous syndactyly.

Any structural anomaly of the heart and blood vessels.

Congenital absence of the anus, i.e., the opening at the bottom end of the intestinal tract.

The presence of a fistula between the vagina and the rectum.

The disorder described by Hirschsprung (1888) and known as Hirschsprung disease or aganglionic megacolon is characterized by congenital absence of intrinsic ganglion cells in the myenteric (Auerbach) and submucosal (Meissner) plexuses of the gastrointestinal tract. Patients are diagnosed with the short-segment form (S-HSCR, approximately 80% of cases) when the aganglionic segment does not extend beyond the upper sigmoid, and with the long-segment form (L-HSCR) when aganglionosis extends proximal to the sigmoid (Amiel et al., 2008). Total colonic aganglionosis and total intestinal HSCR also occur. Genetic Heterogeneity of Hirschsprung Disease Several additional loci for isolated Hirschsprung disease have been mapped. HSCR2 (600155) is associated with variation in the EDNRB gene (131244) on 13q22; HSCR3 (613711) is associated with variation in the GDNF gene (600837) on 5p13; HSCR4 (613712) is associated with variation in the EDN3 gene (131242) on 20q13; HSCR5 (600156) maps to 9q31; HSCR6 (606874) maps to 3p21; HSCR7 (606875) maps to 19q12; HSCR8 (608462) maps to 16q23; and HSCR9 (611644) maps to 4q31-q32. HSCR also occurs as a feature of several syndromes including the Waardenburg-Shah syndrome (277580), Mowat-Wilson syndrome (235730), Goldberg-Shprintzen syndrome (609460), and congenital central hypoventilation syndrome (CCHS; 209880). Whereas mendelian modes of inheritance have been described for syndromic HSCR, isolated HSCR stands as a model for genetic disorders with complex patterns of inheritance. Isolated HSCR appears to be of complex nonmendelian inheritance with low sex-dependent penetrance and variable expression according to the length of the aganglionic segment, suggestive of the involvement of one or more genes with low penetrance. The development of surgical procedures decreased mortality and morbidity, which allowed the emergence of familial cases. HSCR occurs as an isolated trait in 70% of patients, is associated with chromosomal anomaly in 12% of cases, and occurs with additional congenital anomalies in 18% of cases (summary by Amiel et al., 2008).

A congenital abnormality in which the lung parenchyma is not fully developed. It may be associated with other congenital abnormalities.

An abnormal accumulation of fluid beneath the skin, or in one or more cavities of the body.