Joubert syndrome
| Classification according to ICD-10 | |
|---|---|
| Q04.3 | Other reduction deformities of the brain
Aplasia / hypoplasia of a part of the brain |
| ICD-10 online (WHO version 2019) | |
The Joubert syndrome , also known under the synonyms Joubert Boltshauser syndrome , vermis agenesis and cerebello-Parenchymal disruption IV is a genetic complex central nervous system development and function special feature of the people on the basis of a genetic mutation .
The syndrome is congenital, i.e. not acquired in the course of life, although a basic disorder is not yet known.
The independence of Joubert syndrome as a systematically described (= nosological) peculiarity is not yet completely clear due to the lack of a basic disorder. This means that one does not yet know exactly whether it is a separate clinical picture or a combination of different individual diseases.
However, the frequency of occurrence of various peculiarities suggests that it is an independent clinical picture, the symptoms of which have a common basis. That is why it is treated as an independent specialty in specialist books.
frequency
Since the first description of the peculiarity in 1969, over 110 sporadic (= isolated, random) cases and sibling cases have been documented. In at least ten of the cases (mainly in boys ) malformations of the retina in the eye (retinal coloboma) are detectable.
features
The Joubert syndrome is characterized by the absence or extensive underdevelopment of the structure between the two parts of the cerebellum , the vermis cerebelli (Latin: vermis = worm, cerebellum = cerebellum), which usually connects them. Adjacent parts of the cerebellar regions are also severely underdeveloped or missing.
In some of the people with Joubert syndrome special features consist of the iris (Iris), malformations of the retina (retinal), the cell layer between the photoreceptors and the underlying choroid (retinal pigment / RPE) and the choroid (choroid) itself.
Common symptoms
- Prenatal : An open vermis cerebelli, which can be detected by ultrasound after about the 18th week of pregnancy , is a soft marker for Joubert's syndrome
- increased breathing ( hyperpnoea )
- accelerated breathing rate of up to 100 breaths per minute ( tachypnea )
- Breathing pauses / respiratory arrest (apnea)
- Movement disorders / peculiarities of movement sequences ( ataxia )
- Rhythmic forward displacement (protrusion) of the tongue
- involuntary rhythmic movements of the eyes / eye tremors ( nystagmus )
- rhythmic muscle tremors ( tremor )
- cognitive disability
- Bulging of meninges on the back of the head and the penetration of brain tissue into the formed bladder (occipital meningoencephalocele )
- family specific deficiency or misuse or hereditary disorders, and changes in the retina in the eye ( Retinadystrophie ) and the fabric bags in the kidneys , in which liquid or air collects ( cystic kidneys , Frequency: 2%)
- Malformations of the retina (retina), choroid ( choroid ) and optic nerve (optic nerve, frequency: 4%)
Other uncommon symptoms
- a comparatively small head ( microcephaly ),
- Bone marrow growth on the back of the head (occipital myeloma )
- Tumors of the tongue (frequency: 2%),
- Holoprosencephaly
- Polydactyly (variety, frequency 8%)
Development forecast
Experts still do not agree on the life expectancy of children with Joubert syndrome. Many children do not survive childhood, other children have a good development prognosis. Symptomatic therapy or treatment options are now known ( ventilation , continuous monitor monitoring (especially SpO2), intensive care, O2 substitution in apnea / cyanotic conditions, physiotherapy , early intervention , monitoring of head circumference / liver / kidney values, provision of visual aids). However, the syndrome cannot be cured.
genetics
Both sexes are equally often affected. Joubert syndrome follows an autosomal recessive inheritance , which means that a child can only acquire this special feature if its two biological parents are carriers of a certain genetic characteristic and pass it on to the child.
Since cases of Joubert syndrome with and without malformations of the eyes on the iris , retina and choroid have not yet been observed together in a sibling , different genetic characteristics are assumed for both forms.
The partial (partial) absence ( aplasia ) of the cerebellar worm (vermis cerebelli) with only movement disorders ( ataxia ) and eye tremors ( nystagmus ) is probably caused by the X-chromosome, i.e. the triggering gene feature is on the X-chromosome .
diagnosis
The detection of Joubert's syndrome in a child is possible prenatally (= prenatal) in part by methods of prenatal diagnosis using magnetic resonance imaging or fine ultrasound based on the absence or severe underdevelopment of the cerebellar worm (vermis aplasia).
A strong interfamily variability of the clinical symptoms must be taken into account, i.e. the severity of the symptoms can be very different from family to family. A differential diagnosis ( i.e. checking whether the symptoms match another characteristic better) for Rett syndrome and CHOACH can be made on the basis of the early age of onset , i.e. the age at which the characteristic first appeared.
There are genetic and / or clinical relationships to the
- Mohr syndrome , orofazio-digital syndrome type 6 (Varadi-Papp syndrome)
- Meckel syndrome
- Smith-Lemli-Opitz syndrome
- CHARGE association
literature
- R. Witkowski, O. Prokop, E. Ullrich, G. Thiel: Lexicon of Syndromes and Malformations 7th edition. Springer, Berlin 2003, ISBN 3-540-44305-3 .
