Agenesis

Classification

A large number of ageneses can be distinguished:

• L'agenesis of the corpus callosum is one of the most common. The latter is a white substance, part of the brain, and uniting the two cerebral hemispheres. Agenesis of the corpus callosum is either total, partial, isolated, or associated with other malformations, in particular abnormalities in the shape of the brain (cerebral dysmorphism). It may be a macrocephaly, that is to say an abnormal increase in the volume of the head, and a hypertelorism, that is, too great a separation of the eyeballs. It can also be a hypotonia, that is to say a decrease in muscle tone, associated with a delay in walking, and seizures (epilepsy). In this case, the patient presents neurological symptoms, and in particular, most often, cognitive disturbances (concerning intellectual learning) such as mental retardation. Shapiro-Williams syndrome refers to an association between agenesis of the corpus callosum and repeated bouts of spontaneously occurring drop in body temperature accompanied by sweating and disturbances of consciousness. For some neurology specialists, this is a form ofdiencephalic epilepsy.
• L'agenesis members the most common of which is agenesis of the forearm bones, i.e. the ulna and radius, which appear deformed. This skeletal malformation leads to the appearance of a wrist anomaly, most often requiring orthopedic intervention at birth. Other limb agenesis are: ectromelia that is to say malformations characterized by the absence of one or more limb segments. Ectromelia concerns the extremities resulting in the absence of fingers, or the absence of a hand, or even a foot. phocomelia is characterized by malformations of the proximal segment, that is to say the beginning of the limb, or the middle segment. The term hemimelia, on the other hand, designates a more or less total absence of development of the elbow and knee. The term Amelie, means a total absence of one or more members.
• L'agenesis kidneys affects either one organ or both at the same time. This type of malformation affects one in 1500 babies. More rarely, agenesis affects both kidneys, in which case it is the Potter syndrome (one in 4000 newborns). Bilateral kidney failure does not allow the child to live for a long time. Potter syndrome is characterized by insufficient development of the kidneys on both sides (bilateral renal agenesis), malformations of the genital organs, anorectal malformations (of the anus and rectum), insufficient development of the lungs (pulmonary hypoplasia), and a particular appearance of the face called Potter's face, associating a epicanthus (presence of a semilunar fold in the shape of a half-moon formed by the skin located in front of the internal angle of the eye), a hypertelorism (high distance separating the orbits, a retrognathism (recessed jaw and wide ears.
• L'agenesis lungs is relatively rare. Most often, only one lobe is affected. This congenital malformation is associated with other malformations, particularly those of the heart, intestine, stomach, and/or skeleton. Bilateral pulmonary agenesis is, of course, incompatible with prolonged survival.
• L'agenesis of the coccyx is most often associated with agenesis of the sacrum and the lower spine (lumbar vertebrae). This type of anatomical abnormality leads to the appearance of a paralysis of the lower limbs associated with disturbances in the functioning of the urinary system.
• Le Schmorl and Junghanns vertebral block designates the synostosis (fusion of bones) of two or sometimes three vertebrae, resulting in a vicious attitude as can be observed among other things, during theagenesis of the vertebral discThis syndrome can also follow a infectious spondylitisChronic rheumatism or Pott's disease are also likely to lead to the appearance of a vertebral block.
• Le Weyers-Thier syndrome also called oculovertebral syndrome, is a variety of first arc syndrome associating:
• Eye abnormalities such as:
  • Microphthalmia (small eyeball).
  • Anophthalmia (absence of the eye).
  • Coloboma (crack).
  • Aplasia of half the face and malformations of the cervical and dorsal vertebrae such as hemivertebrae (half vertebrae).
  • Wedge-shaped vertebrae or insufficient vertebral development.
• L'agenesis Sabouraud's pilar.