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 presence of multiple cysts in both kidneys.

Reduced volume of the testicle (the male gonad).

An abnormal increase in the size of the kidney.

Accumulation of clear fluid in the between the layers of membrane (tunica vaginalis) surrounding the testis.

Obliteration of the glomerular capillary lumen by increased collagenous matrix, with or without hyalinosis or foam cells. Sclerosis involves 100% of the glomerular tuft. Relative to other patent glomeruli in the sample, glomerular size is preserved, or increased/decreased by no more than 50%.

A widely spaced gap between the first toe (the great toe) and the second toe.

Clinodactyly refers to a bending or curvature of the fifth finger in the radial direction (i.e., towards the 4th finger).

The middle finger is more than 2 SD above the mean for newborns 27 to 41 weeks EGA or above the 97th centile for children from birth to 16 years of age AND the five digits retain their normal length proportions relative to each other (i.e., it is not the case that the middle finger is the only lengthened digit), or, Fingers that appear disproportionately long compared to the palm of the hand.

Visible increase in width of the hallux without an increase in the dorso-ventral dimension.

A condition in which the anterior part of the foot rotates outward away from the midline of the body and the heel remains straight.

Any cardiac rhythm other than the normal sinus rhythm. Such a rhythm may be either of sinus or ectopic origin and either regular or irregular. An arrhythmia may be due to a disturbance in impulse formation or conduction or both.

In utero, the ductus arteriosus (DA) serves to divert ventricular output away from the lungs and toward the placenta by connecting the main pulmonary artery to the descending aorta. A patent ductus arteriosus (PDA) in the first 3 days of life is a physiologic shunt in healthy term and preterm newborn infants, and normally is substantially closed within about 24 hours after bith and completely closed after about three weeks. Failure of physiologcal closure is referred to a persistent or patent ductus arteriosus (PDA). Depending on the degree of left-to-right shunting, PDA can have clinical consequences.

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

Increased size of the heart, clinically defined as an increased transverse diameter of the cardiac silhouette that is greater than or equal to 50% of the transverse diameter of the chest (increased cardiothoracic ratio) on a posterior-anterior projection of a chest radiograph or a computed tomography.

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 type of cardiac arrhythmia with premature atrial contractions or beats caused by signals originating from ectopic atrial sites.

Supraventricular tachycardia (SVT) is an abnormally increased heart rate (over 100 beats per minute at rest) with origin above the level of the ventricles.

A type of ventricular tachycardia characterized by polymorphioc QRS complexes that change in amplitue and cycle length, and thus have the appearance of oscillating around the baseline in the EKG.

A tachycardia originating in the ventricles characterized by rapid heart rate (over 100 beats per minute) and broad QRS complexes (over 120 ms).

Aortic valve disease-2 (AOVD2) is characterized by bicuspid aortic valve (BAV) and dilation of the ascending aorta. Calcification of the valve and the aorta has been observed, and some patients exhibit coarctation of the aorta (Tan et al., 2012; Luyckx et al., 2019; Park et al., 2019). For a general phenotypic description and a discussion of genetic heterogeneity of aortic valve disease, see AOVD1 (109730).

Premature ventricular contractions (PVC) or ventricular extrasystoles are premature contractions of the heart that arise in response to an impulse in the ventricles rather than the normal impulse from the sinoatrial (SA) node.

An abnormal narrowing or constriction of the pulmonary artery, in the main pulmonary artery and/or in the left or right pulmonary artery branches.

Increase in size of the left atrium.

A kind of atrial septum defect arising from an enlarged foramen ovale, inadequate growth of the septum secundum, or excessive absorption of the septum primum.

A ventricular septal defect that is confluent with and involves the membranous septum and is bordered by an atrioventricular valve, not including the type 3 VSDs.

Stenosis of a peripheral branch of the pulmonary artery.

Pulmonary hypertension is defined mean pulmonary artery pressure of 25mmHg or more and pulmonary capillary wedge pressure of 15mmHg or less when measured by right heart catheterisation at rest and in a supine position.

An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.

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.

Slow or limited growth after birth.

Difficulty in swallowing.

Abnormally increased frequency (usually defined as three or more) loose or watery bowel movements a day.

Feeding problem necessitating food and nutrient delivery via a tube.

Yellow pigmentation of the skin due to bilirubin, which in turn is the result of increased bilirubin concentration in the bloodstream.

Forceful ejection of the contents of the stomach through the mouth by means of a series of involuntary spasmic contractions.

Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.

A form of hepatic steatosis characterized by the presence of large, lipid-laden vesicles in the affected hepatocytes.

A form of hepatic steatosis characterized by the presence of small, lipid-laden vesicles in the affected hepatocytes.

Median longitudinal ear length greater than two standard deviations above the mean and median ear width greater than two standard deviations above the mean (objective); or, apparent increase in length and width of the pinna (subjective).

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.

Angle formed by the plane of the ear and the mastoid bone greater than the 97th centile for age (objective); or, outer edge of the helix more than 2 cm from the mastoid at the point of maximum distance (objective).

Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose.

Torticollis is a twisted neck as a result of shortening of sternocleidomastoid muscle. This short and fibrotic muscle pulls the head laterally and rotates the chin and face to the opposite end. Facial asymmetry may be a manifestation (summary by Engin et al., 1997).

Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.

A generalized-onset seizure is a type of seizure originating at some point within, and rapidly engaging, bilaterally distributed networks. The networks may include cortical and subcortical structures but not necessarily the entire cortex.

Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.

A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase.

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.

A severe delay in the achievement of motor or mental milestones in the domains of development of a child.

A proneness to anger, i.e., a tendency to become easily bothered or annoyed.

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

Polycythemia is diagnosed if the red blood cell count, the hemoglobin level, and the red blood cell volume all exceed the upper limits of normal.

A reduction in the number of circulating thrombocytes.

Anemia caused by low iron intake, inefficient iron absorption in the gastrointestinal tract, or chronic blood loss.

Protrusion of the contents of the abdominal cavity through the inguinal canal.

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

Developmental hypoplasia of the mandible.

A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move.

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.

Infants normally have two fontanels at birth, the diamond-shaped anterior fontanelle at the junction of the coronal and sagittal sutures, and the posterior fontanelle at the intersection of the occipital and parietal bones. The posterior fontanelle usually closes by the 8th week of life, and the anterior fontanel closes by the 18th month of life on average. This term applies if there is delay of closure of the fontanelles beyond the normal age.

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.

A form of developmental hypoplasia of the mandible in which the mandible is mislocalised posteriorly.

An enlargement of the posterior fontanelle relative to age-dependent norms.

Vertical bony ridge positioned in the midline of the forehead.

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

A defect of the chest wall characterized by a depression of the sternum, giving the chest ("pectus") a caved-in ("excavatum") appearance.

An abnormally small sella turcica.

Head circumference below 2 standard deviations below the mean for age and gender.

Lack of breathing with no movement of the respiratory muscles and no exchange of air in the lungs. This term refers to a disposition to have recurrent episodes of apnea rather than to a single event.

Fluid accumulation in the lungs.

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

Inspiration of a foreign object into the airway.

A functional defect characterized by reduced total lung capacity (TLC) not associated with abnormalities of expiratory airflow or airway resistance. Spirometrically, a restrictive defect is defined as FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) less than 80 per cent. Restrictive lung disease may be caused by alterations in lung parenchyma or because of a disease of the pleura, chest wall, or neuromuscular apparatus.

Eczema is a form of dermatitis that is characterized by scaly, pruritic, erythematous lesions located on flexural surfaces.

Increased susceptibility to infections.

Increased susceptibility to otitis media, as manifested by recurrent episodes of otitis media.

Localized fluid retention and tissue swelling caused by a compromised lymphatic system.

An increased amount of bilirubin in the blood.

An abnormally increased height of the forehead.

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).

Any abnormality of the teeth.

The palpebral fissure inclination is more than two standard deviations below the mean.

A splitting of the nasal tip. Visually assessable vertical indentation, cleft, or depression of the nasal tip.

Diminished length of the neck.

Height of the vermilion of the medial part of the lip more than 2 SD below the mean, or apparently reduced height of the vermilion of the lip in the frontal view. The vermilion is the red part of the lips (and confusingly, the vermilion itself is also often referred to as being equivalent the lips).

Epicanthus is a condition in which a fold of skin stretches from the upper to the lower eyelid, partially covering the inner canthus. Usher (1935) noted that epicanthus is a normal finding in the fetus of all races. Epicanthus also occurs in association with hereditary ptosis (110100).

Width of the palate more than 2 SD below the mean (objective) or apparently decreased palatal width (subjective).

Decreased density/number of eyebrow hairs.

Thinned, deficient, or excessively arched ala nasi.

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

Forward prominence of the entire forehead, due to protrusion of the frontal bone.

Accentuated, prominent philtral ridges giving rise to an exaggerated groove in the midline between the nasal base and upper vermillion border.

Excess skin around the neck, often lying in horizontal folds.

Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues.

Height of the vermilion of the upper lip in the midline more than 2 SD above the mean. Alternatively, an apparently increased height of the vermilion of the upper lip in the frontal view (subjective).

Width of the forehead or distance between the frontotemporales is more than two standard deviations above the mean (objective); or apparently increased distance between the two sides of the forehead.

Increased breadth of the nasal bridge (and with it, the nasal root).

Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip.

Skin crease extending from below the inner canthus laterally along the malar process of the maxilla and zygoma.

Reduced distance from the anterior border of the naris to the subnasale.

Decreased distance from the nasal tip to the nasal base.

Distance between nasal base and midline upper lip vermilion border more than 2 SD below the mean. Alternatively, an apparently decreased distance between nasal base and midline upper lip vermilion border.

Distance between nasal base and midline upper lip vermilion border more than 2 SD above the mean. Alternatively, an apparently increased distance between nasal base and midline upper lip vermilion border.

Height of the vermilion of the upper lip in the midline more than 2 SD below the mean. Alternatively, an apparently reduced height of the vermilion of the upper lip in the frontal view (subjective).

Exaggerated bulkiness of the crease or fold of skin running from the lateral margin of the nose, where nasal base meets the skin of the face, to a point just lateral to the corner of the mouth (cheilion, or commissure).

An abnormality of the eyelids.

Horizontal crease or fold situated below the vermilion border of the lower lip and above the fatty pad of the chin, with the face at rest.

Inner aspect of the upper lip vermilion (normally apposing the teeth) visible in a frontal view, i.e., the presence of an everted upper lip.

An increased thickness of the eyelid not related to acute inflammation.

Wrinkled, redundant, inelastic and sagging skin.

Excessive wrinkling of the skin of the face.

A capillary malformation is a flat, sharply defined vascular stain of the skin. It may cover a large surface area or it may be scattered and appear as little islands of color. In a capillary maformation, the predominant vessels are small, slow-flow vessels (i.e., arterioles and postcapillary venules).

Hair that is fine or thin to the touch.

Loose and sagging skin often associated with loss of skin elasticity.

Mid upper eyelash length >10 mm or increased length of the eyelashes (subjective).

Diminished amniotic fluid volume in pregnancy.

An abnormal reduction in quantity or strength of fetal movements.

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

Although hypertelorism means an excessive distance between any paired organs (e.g., the nipples), the use of the word has come to be confined to ocular hypertelorism. Hypertelorism occurs as an isolated feature and is also a feature of many syndromes, e.g., Opitz G syndrome (see 300000), Greig cephalopolysyndactyly (175700), and Noonan syndrome (163950) (summary by Cohen et al., 1995).

An eye that is more deeply recessed into the plane of the face than is typical.