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).

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.

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

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

The term 'atrioventricular septal defect' (AVSD) covers a spectrum of congenital heart malformations characterized by a common atrioventricular junction coexisting with deficient atrioventricular septation. In ostium primum atrial septal defect (ASD) there are separate atrioventricular valvar orifices despite a common junction, whereas in complete AVSD the valve itself is also shared (summary by Craig, 2006). AVSD, also designated endocardial cushion defect or atrioventricular canal defect (AVCD), is known to occur in either a nonsyndromic (isolated) form or, more commonly, as part of a malformation syndrome. The 2 syndromes most frequently associated with AVSD are Down syndrome (190685), in which AVSD is the most frequent congenital heart defect, and Ivemark syndrome (208530) (summary by Carmi et al., 1992). Genetic Heterogeneity of Isolated Atrioventricular Septal Defect An AVSD susceptibility locus (AVSD1) maps to chromosome 1p31-p21; AVSD2 (606217) is caused by mutation in the CRELD1 gene (607170) on chromosome 3p25; AVSD4 (614430) is caused by mutation in the GATA4 gene (600576) on chromosome 8p23.1; and AVSD5 (614474) is caused by mutation in the GATA6 gene (601656) on chromosome 18q11. A form of AVSD, designated AVSD3, was thought to be caused by mutation in the GJA1 gene (121014.0011), but this variant has been reclassified as a variant of unknown significance. Somatic mutations in the HAND1 gene (602406) have been identified in tissue samples from patients with AVSDs.

A narrowing of the right ventricular outflow tract that can occur at the pulmonary valve (valvular stenosis), below the pulmonary valve (infundibular stenosis), or above the pulmonary valve (supravalvar stenosis).

A left-right reversal (or "mirror reflection") of the anatomical location of the viscera of the abdomen.

Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention.

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).

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.

Underdevelopment of the vermis of cerebellum.

Exaggerated anterior convexity of the thoracic vertebral column.

Developmental hypoplasia of the mandible.

The distal interphalangeal joint and/or the proximal interphalangeal joint of the fingers or toes cannot be extended to 180 degrees by either active or passive extension.

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

Absence (aplasia) of the spleen.

The palpebral fissure inclination is more than two standard deviations above the mean for age (objective); or, the inclination of the palpebral fissure is greater than typical for age.

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).

A gap in the lip or lips.

An abnormality of dermatoglyphs (fingerprints), which are present on fingers, palms, toes, and soles.

Aplasia or developmental hypoplasia of the nail.

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).

Interpupillary distance less than 2 SD below the mean (alternatively, the appearance of an decreased interpupillary distance or closely spaced eyes).