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).

The legs angle inward, such that the knees are close together and the ankles far apart.

Short (hypoplastic) phalanx of finger, affecting one or more phalanges.

An outward deviation of the foot at the talocalcaneal or subtalar joint.

Underdevelopment of the humerus.

Diminished length of one or more metacarpal bones in relation to the others of the same hand or to the contralateral metacarpal.

Ossification of carpal bones occurs later than age-adjusted norms.

Proximal mislocalization of the thumb.

Absence of the tibia.

Failure of the foramen ovale to seal postnatally, leaving a potential conduit between the left and right cardiac atria.

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 defect of the atrioventricular septum of the heart.

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).

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

Difficulty in swallowing.

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

A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter.

An abnormality of vibrational conductance of sound to the inner ear leading to impairment of sensory perception of sound.

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

Distortion of the course of the normal folds of the ear and the appearance of supernumerary crura and folds.

Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).

A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

Involuntary movements characterized by both athetosis (inability to sustain muscles in a fixed position) and chorea (widespread jerky arrhythmic movements).

Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time.

Underdevelopment of the corpus callosum.

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.

Spasticity (velocity-dependent increase in tonic stretch reflexes with increased muscle tone and hyperexcitable tendon reflexes) in the muscles of the lower limbs, hips, and pelvis.

A generalized tonic seizure is a type of generalized motor seizure characterized by bilateral limb stiffening or elevation, often with neck stiffening without a subsequent clonic phase. The tonic activity can be a sustained abnormal posture, either in extension or flexion, sometimes accompanied by tremor of the extremities.

A type of Developmental delay characterized by a delay in acquiring motor skills.

An increase in size of the ventricular system of the brain.

Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.

Atrophy (wasting) of the cerebellar cortex.

Protrusion of abdominal contents through a defect in the abdominal wall musculature around the umbilicus. Skin and subcutaneous tissue overlie the defect.

Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.

The presence of an abnormal lateral curvature of the spine.

Increased width of the skull.

A decreased rate of skeletal maturation. Delayed skeletal maturation can be diagnosed on the basis of an estimation of the bone age from radiographs of specific bones in the human body.

An omphalocele is an abdominal wall defect limited to an open umbilical ring, and is characterized by the herniation of membrane-covered internal organs into the open base of the umbilical cord. Omphalocele is distinguished from gastroschisis (230750), in which the abdominal wall defect is located laterally to a normally closed umbilical ring with herniation of organs that are uncovered by membranes (summary by Bugge, 2010). On the basis of clinical manifestations, epidemiologic characteristics, and the presence of additional malformations, Yang et al. (1992) concluded that omphalocele and gastroschisis are casually and pathogenetically distinct abdominal wall defects. Omphalocele can be a feature of genetic disorders, such as Beckwith-Wiedemann syndrome (130650) and the Shprintzen-Goldberg syndrome (182210).

Frontal schisis (cleft or cleavage) of vertebral bodies.

Joint hypermobility (ability of a joint to move beyond its normal range of motion) affecting many or all joints of the body. In individuals with Joint hypermobility at multiple sites (usually five or more), the term generalized joint hypermobility is preferred.

A shift from the normally round (convex) appearance of the iliac wing towards a square-like appearance.

The odontoid process, or dens, is a bony projection from the axis (C2) upward into the ring of the atlas (C1) at the top of the spine. During embryogenesis, the body of the odontoid derives from the centrum of the atlas and separates from the atlas, fusing with the superior portion of the axis. If the odontoid is hypoplastic or absent, the attachments for the apical and alar ligaments are missing, allowing for excessive rotation of the atlas, craniocervical instability, and possibly cord compression (summary by Stevens et al., 2009).

Generalized muscular hypotonia (abnormally low muscle tone).

The presence of dysplastic regions in metaphyseal regions.

The chevron sign refers to an inverted V-shape metaphyses. It is most commonly seen in the distal femur and tends to disappear with age.

Laryngomalacia is a congenital abnormality of the laryngeal cartilage in which the cartilage is floppy and prolapses over the larynx during inspiration.

An increased concentration of pyruvate in the blood.

The presence of an abnormal decrease or increase of one or more amino acids in the blood circulation.

Decreased strength of the vocal folds.

Developmental hypoplasia of the dental enamel.

Delayed tooth eruption, which can be defined as tooth eruption more than 2 SD beyond the mean eruption age.

Posterior positioning of the nasal root in relation to the overall facial profile for age.

Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip).

Absence of concavity or convexity of the face when viewed in profile.

The presence of excess amniotic fluid in the uterus during pregnancy.

The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective).

A cataract that occurs congenitally as the result of a developmental defect, in contrast to the majority of cataracts that occur in adulthood as the result of degenerative changes of the lens.

A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.