Holoproencéphalie

The holoproencéphalie is a congenital malformation Cerveau. It consists in the absence of separation of the primitive brain or Télencéphale of two hemispheres and two ventricles.

There exist several types of holoproencéphalie according to the extent of malformation. This malformation involves anomalies associated with the face more or less important. The intellectual delay is very often present. The children reached by the most severe forms live only a few months.

Other names

Incidence

The incidence is of 1 on 10  000 with 20  000 births.

Definition

According to the importance of malformation one distinguishes:
  • Holoproencéphalie alobaire : most severe with complete absence of cerebral cleavage and a single ventricle cerebral.
  • Holoproencéphalie semi-lobaire : the frontal and parietal zones of the brain are amalgamated. The interhemispheric fissure is present only in the posterior part.
  • Holoproencéphalie lobaire : the brain is separate in the greatest part; only the frontal part of the brain is amalgamated.

There exists a form of holoproencéphalie which sits only in the middle of the interhemispheric line, or syntéléencéphalie . It is not known if this form is a particular entity of holoproencéphalie or a particular entity.

Description

In addition to the anomaly of the brain, the fetus often presents anomalies of the face in connection with the type of the holoproencéphalie. The anomalies of the face are very common:
  • Reduction in the inter-orbital distance being able to go until a cyclopism
  • labio-palatine Division generally median
  • Absence of a eye or in both Eyes
  • But sometimes physical appearance is not any indicator

Diagnosis anténatal

  • the diagnosis anténatal is easy in the event of holoproencéphalie alobaire or semi lobaire is made at the time of the morphological echography S. The diagnosis is more difficult in the event of holoproencéphalie lobaire. The realization of a Imagerie to magnetic resonance makes the diagnosis in case of doubt.
  • a medical Interruption of pregnancy is accepted in the majority of the holoproencéphalies.

Causes

Maternal disease

  • the maternal diabetes increases by 200 the risk of holoproencéphalie.

Poisons

  • Of the recent studies shows the possibility that the Hypolipémiant S of the class of the Statine S can be implied in occurred of holoproencéphalie.

chromosomal Diseases

  • Responsible for 25 to 50% of the holoproencéphalies

Anomaly of the number

Anomaly of the structure

All the chromosomes are likely to produce a holoproencéphalie in case modification of their structure like:
  • Délétion
  • Duplication

Genetic diseases

Persons in charge of 25% of the holoproencéphalies. More than 25 genetic diseases comprise a holoproencéphalie like characteristic:

Syndromiques autosomal dominating

Syndrome of Pallister-Hall
Syndrome of Rubinstein-Taybi
Syndrome of Martin
Syndrome of $kalman
Syndrome of Steinfeld
  • Holoprosencéphalie with Cardiopathie, absence of Gall bladder and hypoplasy of the Radius and the Ulna
With hypertelorism

Recessive Syndromique autosomal

Pseudo-trisomy 13
Syndrome of Smith-Lemli-Opitz
Syndrome of Meckel
Hydrolethalus syndrome
Syndrome of Lambotte

Syndrome of Genoa
  • Holoprosencéphalie with Craniosténose
With absence of upper limb

Syndromique of unknown transmission

Caudal disgenesis

Nonsyndromic

Several genetic mutations can be at the origin of holoproencéphalie. These changes are of dominant autosomic Transmission
Gene SHH located on the chromosome 7
Gene ZIC2 located on the chromosome 13
Gene SIX3 located on the chromosome 2
Gene TGIF located on the chromosome 18
Gene PTCH located on the chromosome 9

The genetic Council

The genetic Conseil depends on the results of the medical investigations carried out.

Sources

  • Site of information on the orphan rare diseases and drugs
  • Site impossible to circumvent for the genetic diseases
  • Site describing in a very pointed way the genetic diseases

See too

Random links:Battle of Issos | Chronicles of Riddick | Talasani | Philippe Courroye | Lake Piedra del Águila | Le_Havre_occidental,_Montana