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).

A connection of the right and left kidney by an isthmus of functioning renal parenchyma or fibrous tissue that crosses the midline.

Midline indentation or cleft of the scrotum.

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.

Developmental hypoplasia of the clitoris.

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.

Clubfoot is a congenital limb deformity defined as fixation of the foot in cavus, adductus, varus, and equinus (i.e., inclined inwards, axially rotated outwards, and pointing downwards) with concomitant soft tissue abnormalities (Cardy et al., 2007). Clubfoot may occur in isolation or as part of a syndrome (e.g., diastrophic dysplasia, 222600). Clubfoot has been reported with deficiency of long bones and mirror-image polydactyly (Gurnett et al., 2008; Klopocki et al., 2012).

Digits that appear disproportionately short compared to the hand/foot. The word brachydactyly is used here to describe a series distinct patterns of shortened digits (brachydactyly types A-E). This is the sense used here.

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

Webbing or fusion of the 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 toes in a proximo-distal axis are referred to as "Symphalangism".

A type of knee joint contracture in which the knee is in a fixed bent (flexed) configuration such that it cannot be straightened actively or passively.

Increased thumb width without increased dorso-ventral dimension.

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

A condition in which middle parts of the foot (toes and metatarsals) are missing giving a cleft appearance. The severity is very variable ranging from slightly hypoplastic 3rd toe over absent 2nd or 3rd toes as far as oligo- or monodactyl feet.

Underdevelopment of the radius.

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

Underdevelopment of the fibula.

A toe that appears disproportionately short compared to the foot.

Absence or underdevelopment of the big toe.

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

Underdevelopment of the patella.

Diminished length of a metatarsal bone, with resultant proximal displacement of the associated toe.

Absence or underdevelopment of the femur.

Underdevelopment of the ulna.

Proximal mislocalization of the thumb.

Shortening of the middle parts of the leg in relation to the upper and terminal segments.

Duplication of all or part of the first ray.

A condition in which middle parts of the hand (fingers and metacarpals) are missing giving a cleft appearance. The severity is very variable ranging from slightly hypoplastic middle fingers over absent middle fingers as far as oligo- or monodactyl hands.

Absence of the tibia.

Absence (due to failure to form) or underdevelopment of the humerus.

The metatarsals are deviated medially (tibially), that is, the bones in the front half of the foot bend or turn in toward the body.

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.

Total anomalous pulmonary venous return (TAPVR) is a cyanotic form of congenital heart defect in which the pulmonary veins fail to enter the left atrium and instead drain into the right atrium or one of the venous tributaries (summary by Bleyl et al., 1994).

A decreased magnitude of the sensory perception of sound.

A condition in which the helix is folded over to a greater degree than normal. That is, excessive curling of the helix edge, whereby the free edge is parallel to the plane of the ear.

Laterally protruding ear that lacks antihelical folding (including absence of inferior and superior crura).

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).

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.

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.

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

Displacement of the femur from its normal location in the hip joint.

Developmental hypoplasia of the mandible.

Reduced length of the clavicles.

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.

Underdevelopment of the ischium, which forms the lower and back part of the hip bone.

Underdevelopment of the ilium ala.

Widening of the ilium ala, that is of the wing of the ilium, combined with external rotation, leading to a flared appearance of the iliac wing.

Underdevelopment of a ramus (branch) of the pubic bone.

An abnormally wavy surface or edge of the ribs.

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

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

The presence of symmetrical and circular openings (foramina) in the parietal bone ranging in size from a few millimeters to several centimeters wide.

A fixed reduction in the vertical distance between the upper and lower eyelids with short palpebral fissures.

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).

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).

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.

Gentle upward curve of the upper lip vermilion such that the center is placed well superior to the commissures.

Skin dimples are cutaneous indentations that are the result of tethering of the skin to underlying structures (bone) causing an indentation.

A developmental defect resulting in the congenital absence of skin on the scalp.

Aplasia or developmental hypoplasia of the nail.

A rudimentary tag of skin often containing ear tissue including a core of cartilage and located just anterior to the auricle (outer part of the ear).

Antecubital pterygium syndrome is an autosomal dominant disorder characterized by a fleshy web extending across the anterior aspect of the cubital fossa, absence of the long head of the triceps, limitation of full elbow extension, and missing skin creases over the terminal interphalangeal joints of the fingers (summary by Wallis et al., 1988).

A pterygium (or pterygia) occurring in the popliteal region (the back of the knee).

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).

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).

Microphthalmia is an eye abnormality that arises before birth. In this condition, one or both eyeballs are abnormally small. In some affected individuals, the eyeball may appear to be completely missing; however, even in these cases some remaining eye tissue is generally present. Such severe microphthalmia should be distinguished from another condition called anophthalmia, in which no eyeball forms at all. However, the terms anophthalmia and severe microphthalmia are often used interchangeably. Microphthalmia may or may not result in significant vision loss.\n\nPeople with microphthalmia may also have a condition called coloboma. Colobomas are missing pieces of tissue in structures that form the eye. They may appear as notches or gaps in the colored part of the eye called the iris; the retina, which is the specialized light-sensitive tissue that lines the back of the eye; the blood vessel layer under the retina called the choroid; or in the optic nerves, which carry information from the eyes to the brain. Colobomas may be present in one or both eyes and, depending on their size and location, can affect a person's vision.\n\nPeople with microphthalmia may also have other eye abnormalities, including clouding of the lens of the eye (cataract) and a narrowed opening of the eye (narrowed palpebral fissure). Additionally, affected individuals may have an abnormality called microcornea, in which the clear front covering of the eye (cornea) is small and abnormally curved.\n\nBetween one-third and one-half of affected individuals have microphthalmia as part of a syndrome that affects other organs and tissues in the body. These forms of the condition are described as syndromic. When microphthalmia occurs by itself, it is described as nonsyndromic or isolated.