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).

Vesicoureteral reflux (VUR) is characterized by the reflux of urine from the bladder into the ureters and sometimes into the kidneys. It is a risk factor for urinary tract infections. Primary VUR results from a developmental defect of the ureterovesical junction (UVJ). In combination with intrarenal reflux, the resulting inflammatory reaction may result in renal injury or scarring, also called reflux nephropathy (RN). Extensive renal scarring impairs renal function and may predispose patients to hypertension, proteinuria, and renal insufficiency (summary by Lu et al., 2007). Genetic Heterogeneity of Vesicoureteral Reflux A locus designated VUR1 maps to chromosome 1p13. VUR2 (610878) is caused by mutation in the ROBO2 gene (602431) on chromosome 3p12; VUR3 (613674) is caused by mutation in the SOX17 gene (610928) on chromosome 8q11; VUR4 (614317) maps to chromosome 5; VUR5 (614318) maps to chromosome 13; VUR6 (614319) maps to chromosome 18; VUR7 (615390) maps to chromosome 12; and VUR8 (615963) is caused by mutation in the TNXB gene (600985) on chromosome 6p21. A possible X-linked form has been reported (VURX; 314550).

Hypertrophy of the clitoris.

Abnormal position of urethral meatus on the ventral penile shaft (underside) characterized by displacement of the urethral meatus from the tip of the glans penis to the ventral surface of the penis, scrotum, or perineum.

Abnormally small penis. At birth, the normal penis is about 3 cm (stretched length from pubic tubercle to tip of penis) with micropenis less than 2.0-2.5 cm.

Narrowing of the urethra associated with inflammation or scar tissue.

Broadening of the soft tissues (non-edematous swelling of soft tissues) of the digital tips in all dimensions associated with an increased longitudinal and lateral curvature of the nails.

A dislocation of the head of the radius from its socket in the elbow joint.

Supernumerary digits located at the radial side of the hand. Polydactyly (supernumerary digits) involving the thumb occurs in many distinct forms of high variability and severity. Ranging from fleshy nubbins over varying degrees of partial duplication/splitting to completely duplicated or even triplicated thumbs or preaxial (on the radial side of the hand) supernumerary digits.

Absence or underdevelopment of the patella.

A soft tissue continuity in the anteroposterior axis between the second (index) to the fourth (ring) finger that extends distally to at least the level of the proximal interphalangeal joints.

Syndactyly with fusion of toes two and three.

Impaired conduction of cardiac impulse occurring anywhere along the conduction pathway.

Atrial septal defect (ASD) is a congenital abnormality of the interatrial septum that enables blood flow between the left and right atria via the interatrial septum.

A hole between the two bottom chambers (ventricles) of the heart. The defect is centered around the most superior aspect of the ventricular septum.

A congenital heart defect characterized by a specific combination of heart defects with a common atrioventricular valve, primum atrial septal defect and inlet ventricular septal defect.

An intermittent atrioventricular block with failure of some atrial impulses to conduct to the ventricles, i.e., some but not all atrial impulses are conducted through the atrioventricular node and trigger ventricular contraction.

A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).

A deficiency or slowing down of growth pre- and postnatally.

Abnormally low body weight.

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

The narrowing or partial blockage of a portion of the duodenum.

Abnormal narrowing of the anal opening.

Anterior malposition of the anus.

A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.

Underdevelopment of the external ear.

Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear.

A decreased magnitude of the sensory perception of sound.

A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.

Arnold-Chiari type I malformation refers to a relatively mild degree of herniation of the posteroinferior region of the cerebellum (the cerebellar tonsils) into the cervical canal with little or no displacement of the fourth ventricle. It is characterized by one or both pointed (not rounded) cerebellar tonsils that project 5 mm below the foramen magnum, measured by a line drawn from the basion to the opisthion (McRae Line)

Craniosynostosis refers to the premature closure of the cranial sutures. Primary craniosynostosis refers to the closure of one or more sutures due to abnormalities in skull development, and secondary craniosynostosis results from failure of brain growth.

The presence of an abnormal lateral curvature of the spine.

A kind of craniosynostosis affecting the sagittal suture.

An abnormality related to a defect of vertebral separation during development.

The capability that a joint (or a group of joints) has to move, passively and/or actively, beyond normal limits along physiological axes.

Progressive microcephaly is diagnosed when the head circumference falls progressively behind age- and gender-dependent norms.

Enlargement of the anterior fontanelle with respect to age-dependent norms.

Diffuse prominent gyral impressions on the inner table of skull vault said to resemble beaten copper.

A bending or abnormal curvature affecting a long bone of the leg.

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

Peritonitis caused by intrauterine intestinal rupture and spillage of fetal meconium into the fetal peritoneal cavity. Intra-peritoneal meconium usually calcifies, sometimes within 24 hours. Ultrasound findings may include intraabdominal calcifications.

Absence or abnormal closure of the choana (the posterior nasal aperture). Most embryologists believe that posterior choanal atresia results from a failure of rupture between the 35th and 38th day of fetal life of the partition which separates the bucconasal or buccopharyngeal membranes. The resultant choanal atresia may be unilateral or bilateral, bony or membranous, complete or incomplete. In over 90 per cent of cases the obstruction is bony, while in the remainder it is membranous. The bony type of atresia is commonly located 1-2 mm. anterior to the posterior edge of the hard palate, and the osseous septum varies in thickness from 1 to 10 mm. In the membranous form of choanal atresia the obstruction usually occurs further posteriorly. In approximately one third of cases the atresia is bilateral.

Distance between the commissures of the mouth more than 2 SD below the mean. Alternatively, an apparently decreased width of the oral aperture (subjective).

Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).

Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate).

Decreased diameter of eyebrow hairs.

Failure to develop and congenital absence of the breast.

An eye that is protruding anterior to the plane of the face to a greater extent than is typical.

Nearsightedness, also known as myopia, is an eye condition that causes blurry distance vision. People who are nearsighted have more trouble seeing things that are far away (such as when driving) than things that are close up (such as when reading or using a computer). If it is not treated with corrective lenses or surgery, nearsightedness can lead to squinting, eyestrain, headaches, and significant visual impairment.\n\nNearsightedness usually begins in childhood or adolescence. It tends to worsen with age until adulthood, when it may stop getting worse (stabilize). In some people, nearsightedness improves in later adulthood.\n\nFor normal vision, light passes through the clear cornea at the front of the eye and is focused by the lens onto the surface of the retina, which is the lining of the back of the eye that contains light-sensing cells. People who are nearsighted typically have eyeballs that are too long from front to back. As a result, light entering the eye is focused too far forward, in front of the retina instead of on its surface. It is this change that causes distant objects to appear blurry. The longer the eyeball is, the farther forward light rays will be focused and the more severely nearsighted a person will be.\n\nNearsightedness is measured by how powerful a lens must be to correct it. The standard unit of lens power is called a diopter. Negative (minus) powered lenses are used to correct nearsightedness. The more severe a person's nearsightedness, the larger the number of diopters required for correction. In an individual with nearsightedness, one eye may be more nearsighted than the other.\n\nEye doctors often refer to nearsightedness less than -5 or -6 diopters as "common myopia." Nearsightedness of -6 diopters or more is commonly called "high myopia." This distinction is important because high myopia increases a person's risk of developing other eye problems that can lead to permanent vision loss or blindness. These problems include tearing and detachment of the retina, clouding of the lens (cataract), and an eye disease called glaucoma that is usually related to increased pressure within the eye. The risk of these other eye problems increases with the severity of the nearsightedness. The term "pathological myopia" is used to describe cases in which high myopia leads to tissue damage within the eye.

A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error.