What is the difference between malformation and deformation

Deformations usually occur in late fetal life and are caused by lack of fetal movement through mechanical, malformational or functional factors. Examples include craniofacial asymmetry, arthrogryposis and talipes. Mechanical causes include uterine anomalies and abnormal fetal positions.

Malformations such as spina bifida can cause intrinsic lack of movement leading to a deformation - talipes, for instance ; renal agenesis results in a lack of amniotic fluid which constrains movement giving a "squashed appearance". Functional disorders include fetal neuromuscular disorders neonatal myotonic dystrophy, spinal muscular atrophy.

A disruption is due to a destructive force acting upon an otherwise normal developing structure. Anomalies caused by disruptive forces can present a particularly distinctive appearance because of the loss of tissue and aberrant differentiation of adjacent tissues with which adhesions may have developed. The mechanisms include cell death or tissue destruction due to vascular anomalies, anoxia, teratogens, infections, or mechanical forces. Characterization of all major and minor anomalies in great detail as precisely as possible is essential to help arrive at the correct diagnosis.

Most often, it is not just one major anomaly or one minor anomaly that makes a diagnosis but rather it is a constellation of major and minor anomalies that point to a specific syndrome diagnosis or known association. Understand the importance and utility of genetic counseling and genetic evaluations in the diagnostic work-up of individuals with congenital anomalies. Understand the roles of a genetic counselor in the case of stillborn infants including the importance of non-directive counseling and special issues related to infant or fetal death.

It is usually not a good time for parents to make future reproductive choices at the time of the death of a child. Thus, it is best to have families return to clinic a few weeks or months after the loss for further counseling. Understand the concepts of:. A syndrome is generally recognized and defined as a well-characterized constellation of major and minor anomalies that occur together in a predictable fashion presumably due to a single underlying etiology which may be monogenic, chromosomal, mitochondrial, or teratogenic in origin.

A sequenc e is a group of related anomalies that generally stem from a single initial major anomaly that alters the development of other surrounding or related tissues or structures. These features along with poor lung development are secondary to decreased amounts of amniotic fluid oligohydramnios which is most often due to major renal kidney abnormalities eg a single major anomaly associated with decreased fetal urine output.

The term field defect is often used to describe related malformations in a particular region and sometimes is used interchangeably with sequence. The Pierre-Robin sequence is in fact sometimes referred to as a field defect where a small jaw resulting in posterior displacement of the tongue causes a cleft palate.

Thus, these birth defects are related to one another in a temporal and physical sense - being limited to that field or area of the head. Spina bifida with changes to the lower extremities and disruption of bowel and bladder dysfunction would be another example of a sequence or field defect. Clubfoot, congenital hip dislocation, and infantile mandibular asymmetry not based on mandibular malformation serve as examples. The musculoskeletal system is involved in almost all deformations.

Various disturbances of intrauterine movement are the usual causes and commonly occur during the fetal period. Causes may be mechanical or malformational.