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 left-right reversal (or "mirror reflection") of the anatomical location of the major thoracic and abdominal organs.

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

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.

A congenital malformation characterized by the union or approximation of the ears in front of the neck, often accompanied by the absence or defective development of the lower jaw.

Nonsyndromic holoprosencephaly is an abnormality of brain development that also affects the head and face. Normally, the brain divides into two halves (hemispheres) during early development. Holoprosencephaly occurs when the brain fails to divide properly into the right and left hemispheres. This condition is called nonsyndromic to distinguish it from other types of holoprosencephaly caused by genetic syndromes, chromosome abnormalities, or substances that cause birth defects (teratogens). The severity of nonsyndromic holoprosencephaly varies widely among affected individuals, even within the same family.\n\nNonsyndromic holoprosencephaly can be grouped into four types according to the degree of brain division. From most to least severe, the types are known as alobar, semi-lobar, lobar, and middle interhemispheric variant (MIHV). In the most severe forms of nonsyndromic holoprosencephaly, the brain does not divide at all. These affected individuals have one central eye (cyclopia) and a tubular nasal structure (proboscis) located above the eye. Most babies with severe nonsyndromic holoprosencephaly die before birth or soon after. In the less severe forms, the brain is partially divided and the eyes are usually set close together (hypotelorism). The life expectancy of these affected individuals varies depending on the severity of symptoms.\n\nPeople with nonsyndromic holoprosencephaly often have a small head (microcephaly), although they can develop a buildup of fluid in the brain (hydrocephalus) that causes increased head size (macrocephaly). Other features may include an opening in the roof of the mouth (cleft palate) with or without a split in the upper lip (cleft lip), one central front tooth instead of two (a single maxillary central incisor), and a flat nasal bridge. The eyeballs may be abnormally small (microphthalmia) or absent (anophthalmia).\n\nSome individuals with nonsyndromic holoprosencephaly have a distinctive pattern of facial features, including a narrowing of the head at the temples, outside corners of the eyes that point upward (upslanting palpebral fissures), large ears, a short nose with upturned nostrils, and a broad and deep space between the nose and mouth (philtrum). In general, the severity of facial features is directly related to the severity of the brain abnormalities. However, individuals with mildly affected facial features can have severe brain abnormalities. Some people do not have apparent structural brain abnormalities but have some of the facial features associated with this condition. These individuals are considered to have a form of the disorder known as microform holoprosencephaly and are typically identified after the birth of a severely affected family member.\n\nMost people with nonsyndromic holoprosencephaly have developmental delay and intellectual disability. Affected individuals also frequently have a malfunctioning pituitary gland, which is a gland located at the base of the brain that produces several hormones. Because pituitary dysfunction leads to the partial or complete absence of these hormones, it can cause a variety of disorders. Most commonly, people with nonsyndromic holoprosencephaly and pituitary dysfunction develop diabetes insipidus, a condition that disrupts the balance between fluid intake and urine excretion. Dysfunction in other parts of the brain can cause seizures, feeding difficulties, and problems regulating body temperature, heart rate, and breathing. The sense of smell may be diminished (hyposmia) or completely absent (anosmia) if the part of the brain that processes smells is underdeveloped or missing.

The corpus callosum is the largest fiber tract in the central nervous system and the major interhemispheric fiber bundle in the brain. Formation of the corpus callosum begins as early as 6 weeks' gestation, with the first fibers crossing the midline at 11 to 12 weeks' gestation, and completion of the basic shape by age 18 to 20 weeks (Schell-Apacik et al., 2008). Agenesis of the corpus callosum (ACC) is one of the most frequent malformations in brain with a reported incidence ranging between 0.5 and 70 in 10,000 births. ACC is a clinically and genetically heterogeneous condition, which can be observed either as an isolated condition or as a manifestation in the context of a congenital syndrome (see MOLECULAR GENETICS and Dobyns, 1996). Also see mirror movements-1 and/or agenesis of the corpus callosum (MRMV1; 157600). Schell-Apacik et al. (2008) noted that there is confusion in the literature regarding radiologic terminology concerning partial absence of the corpus callosum, where various designations have been used, including hypogenesis, hypoplasia, partial agenesis, or dysgenesis.

Developmental hypoplasia of the mandible.

Absence of the mandible.

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

Underdevelopment of the larynx.

Respiratory distress is objectively observable as the physical or emotional consequences from the experience of dyspnea. The physical presentation of respiratory distress is generally referred to as labored breathing, while the sensation of respiratory distress is called shortness of breath or dyspnea.

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.

Hypoplasia of the epiglottis.

Decreased length and width of the tongue.

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

Absence of the tongue owing to a developmental abnormality.

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

Interalar distance more than two standard deviations above the mean for age, i.e., an apparently increased width of the nasal base and alae.

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).

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

Any abnormality of the eye, including location, spacing, and intraocular abnormalities.