A deformity of foot and ankle that has different subtypes that are talipes equinovarus, talipes equinovalgus, talipes calcaneovarus and talipes calcaneovalgus.

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

A defect of development of the brain characterized by replacement of greater portions of the cerebral hemispheres and the corpus striatum by cerebrospinal fluid (CSF) and glial tissue.

Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation.

A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

Inability to initiate changes in activity or movement and to perform ordinary volitional movements rapidly and easily.

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.

Polymicrogyria is a congenital malformation of the cerebral cortex characterized by abnormal cortical layering (lamination) and an excessive number of small gyri (folds).

Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time.

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 brainstem.

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

A limitation in the passive range of motion of the elbow resulting from loss of elasticity in the periarticular tissues owing to structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules or skin. A contracture prevents movement of the associated body part.

Dandy-Walker malformation is defined by hypoplasia and upward rotation of the cerebellar vermis and cystic dilation of the fourth ventricle. Affected individuals often have motor deficits such as delayed motor development, hypotonia, and ataxia; about half have mental retardation and some have hydrocephalus. DWM is a heterogeneous disorder. The low empiric recurrence risk of approximately 1 to 2% for nonsyndromic DWM suggests that mendelian inheritance is unlikely (summary by Murray et al., 1985).

Developmental hypoplasia of the mandible.

Underdevelopment of the musculature.

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

A cystic lymphatic lesion of the neck.

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).

Pterygia are 'winglike' triangular membranes occurring in the neck, eyes, knees, elbows, ankles or digits.

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

The birth of a baby of less than 37 weeks of gestational age.