Developmental Anomalies and Malformations

Developmental anomalies ordinarily have their origins during embryonic life when the development of most body structures begin.

When the damage of epiphyseal cartilage of femur of child or animal due to chronic osteomyelitis, the bone grows no more and the organism has a shortened and deformed leg. It is known as malformation.

Developmental anomalies and malformations include-

Ø   Failure of a structure to disappear, e.g.,

–        Persistence of ductus arteriosus,

–        Persistent foramen ovale, 

–        Interventricular septal defect,

–        Atresia ani.

–        Aberrant structures, e.g.,

–        Pancreatic tissue in the wall of stomach,

–        Adrenal tissue in kidney or testis,

–        Dermoid cyst in the skin,

–        Dentigenous cysts in head and neck,

–        Ectopia cordis.

–         Duplications, e.g.,

–        Partial duplication of head (diprosopia),

–        Twin kitten joined at abdomen where one is only partially developed (heteradelphia),

–        Twin pigs joined at the thorax (thoracopagus).

Causes

Ø   Viral infections, e.g., BVD causes cerebellar hypoplasia in calf,

Ø   Intrauterine exposure to poisons ingested by mother, e.g.,

–        Veratrum californicum causes absence of palate.

–        Thalidomide causes no development of leg

Ø   Vitamin deficiency, e.g.,

–        Vit. A deficiency causes microphthalmia, corneal dermoid,

–        Folic acid deficiency causes leukopenia, macrocytic anemia

Ø  Genetic factors- genetic mutations may cause abnormal growth of any organ.