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).

An abnormality affecting one or both hands.

The presence of chronic increased pressure in the systemic arterial system.

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.

Smaller than normal size according to sex and gestational age related norms, defined as a weight below the 10th percentile for the gestational age.

A kind of short stature in which different regions of the body are shortened to a comparable extent.

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.

Incomplete closure of the embryonic neural tube, whereby some vertebral arches remain unfused and open. The mildest form is spina bifida occulta, followed by meningocele and meningomyelocele.

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

Hyperactivity is a condition characterized by constant and unusually high levels of activity, even in situations where it is deemed inappropriate.

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.

Obstructive sleep apnea is a common, chronic, complex disease associated with serious cardiovascular and neuropsychologic sequelae and with substantial social and economic costs (Palmer et al., 2003).

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.

Abnormally increased curvature (anterior concavity) of the lumbar or cervical spine.

Developmental hypoplasia of the mandible.

A developmental malformation of the occipital bone and upper end of the cervical spine, in which the latter appears to have pushed the floor of the occipital bone upward such that there is an abnormal flattening of the skull base.

The presence of an abnormal lateral curvature of the spine.

Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline.

An abnormality of skull shape characterized by a decreased anterior-posterior diameter. That is, a cephalic index greater than 81%. Alternatively, an apparently shortened anteroposterior dimension (length) of the head compared to width.

An abnormality of skull shape characterized by a increased anterior-posterior diameter, i.e., an increased antero-posterior dimension of the skull. Cephalic index less than 76%. Alternatively, an apparently increased antero-posterior length of the head compared to width. Often due to premature closure of the sagittal suture.

Scaphocephaly is a subtype of dolichocephaly where the anterior and posterior aspects of the cranial vault are pointed (boat-shaped). Scaphocephaly is caused by a precocious fusion of sagittal suture without other associated synostosis.

Ribs with a reduced diameter.

Reduced diameter of a long bone.

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

Abnormal widening of the metaphyseal regions of long bones.

A less than normal number of sternal ossification centers. The sternum is initially formed from bilateral sternal plates that chondrify and begin to fuse with ribs at 10 weeks gestational age. Ossification starts in the manubrium and upper part of the sternal body at the 6th month, in the middle of the sternal body at the 7th month, in the lower part of the body during the 1st postnatal year and in the xiphoid process between years 5 and 18. The number of ossification centers vary up to six, and it is the ossification centers that are visualized by prenatal ultrasound. This term describes a reduction in the number of ossification centers compared with age-related norms.

The presence of an abnormally thin calvarium.

Parietal bossing is a marked prominence in the parietal region.

Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation.

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

The presence of extra bones within a cranial suture. Wormian bones are irregular isolated bones which appear in addition to the usual centers of ossification of the cranium.

A morphological anomaly of the rib cage.

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

An increased susceptibility to pneumonia as manifested by a history of recurrent episodes of pneumonia.

Congenital tracheomalacia is a rare condition where the trachea is soft and flexible causing the tracheal wall to collapse when exhaling, coughing or crying, that usually presents in infancy, and that is characterized by stridor and noisy breathing or upper respiratory infections. Tracheomalacia improves by the age of 18-24 months.

An increased susceptibility to respiratory infections as manifested by a history of recurrent respiratory infections.

Dental malocclusion refers to an abnormality of the occlusion, or alignment, of the teeth and the way the upper and lower teeth fit together, resulting in overcrowding of teeth or in abnormal bite patterns.

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

A tooth present at birth or erupting within the first month of life.

The presence of one or more teeth additional to the normal number.

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).

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

Interalar distance more than 2 SD below the mean for age, or alternatively, an apparently decreased width of the nasal base and alae.

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).

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.

The presence of a high and narrow palate.

An abnormal configuration of the lower lip such that it is turned outward i.e., everted, with the Inner aspect of the lower lip vermilion (normally opposing the teeth) being visible in a frontal view.

Anterior positioning of the nasal root in comparison to the usual positioning for age.

Decreased number of hairs per unit area of skin of the scalp.

Agenesis specifically affecting one of the classes incisor, premolar, or molar.

Telangiectasias refer to small dilated blood vessels located near the surface of the skin or mucous membranes, measuring between 0.5 and 1 millimeter in diameter. Telangiectasia are located especially on the tongue, lips, palate, fingers, face, conjunctiva, trunk, nail beds, and fingertips.

Partial or complete wasting (atrophy) of the skin.

Skin characterized by the lack of natural or normal moisture.

Hair that is fine or thin to the touch.

Decreased density/number of eyelashes.

Reduced density of hairs.

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.

Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.

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.

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

A cleft of the optic nerve that extends inferiorly.

A coloboma of the iris.

Absence of a region of the retina, retinal pigment epithelium, and choroid.

An abnormal bluish coloration of the sclera.