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Rare genetic disease

On the region of chromosome 2p25.3

Including the MYT1L gene

In the form of a deletion or a mutation

Inherited from a symptomatic parent or "de novo"

MYT1L gene syndrome

  • During a medical consultation, genetic analyzes may be indicated .


  • The genetic analyzes can be carried out on the patient alone or, in trio, on the patient and his parents.


  • Two types of gene mutations  MYT1L  can be found:

        - Deletions : loss of part or all of the gene

        - Point variations : anomalies in the  gene sequence

  • The high-throughput sequencing technique, or NGS for next-generation sequencing, is used to identify point variations in the gene . It brings together the sequencing of the exome or the genome. Analysis using a CGH-array or DNA chip technique makes it possible to identify the deletions of MYT1L.


  • In the context of the syndrome linked to the MYT1L gene, deletions and variations in the sequence of the gene are responsible for one and the same pathology.


  • A person with this syndrome has  50% probability of transmitting it to its descendants.   ​ For a  non-carrier couple having had a first child carrying a so-called anomaly "  de novo  » , The recurrence for a next pregnancy is very low .


  • In the event of a request for genetic counseling, only a targeted genetic examination can determine the status of the fetus . Pregnancy is often unremarkable.

                           It is to be emphasized  :

📍 "Duplications of the MYT1L gene are at the origin of a pathology which currently seems different from that linked to deletions / variations of sequence, even if certain clinical aspects may be similar.

Studies are underway to better understand the physio-pathological mechanisms linked to duplications and thus to specify the phenotype of this pathology. "📍

But concretely,  what is MYT1L ?

  • A gene that is expressed mainly antenatally and almost exclusively in the central nervous system .

  • A gene involved in the process of neurogenesis  (maturation of neurons in particular).

  • A syndrome manifested by global developmental delay  with heterogeneous profiles . Not all patients have all the impacts of the syndrome, and the severity of these impacts varies from a patient to another.

  • A non-degenerative pathology.

  DESCRIPTION  from  IMPACTS  from  syndrome  MYT1L   

Predominant delay
on language

Expressive ruble, the median of first sentences is around 5 years old

Intellectual disability 
Learning Disabilities

  • 70%of Intellectual disability to varying degrees

  • 30%of Learning Disabilities (dyslexia, dysphasia, dyspraxia...)


Weight Disorders
and or
Eating disorders

  • 58% Weight Disorders 

- 23% overweight

- 35% with obesity

  • 45% having Eating Disorders (hyperphagia, tachyphagia, impulsivity... more rarely oral disorders)

  • 42% have a normal weight

Behavioral Disorders
almost 100%
alone or in association

  • 55% stereotypies

  • 53% impulsiveness, frustration intolerance

  • 45% auto or hetero aggression

  • 43% with autism spectrum disorder

  • 38% with attention deficit disorder with or without hyperactivity

Psychomotor development disorder

  • Median age of walking acquisition at 22 months

  • Coordination disorder, motor instability, impact on fine motor skills

  • Hypotonia


Epilepsy, brain MRI abnormalities

  • 28% of brain MRI abnormalities


  • 23% of epilepsy

Other Observed Disorders

  • 33%  sleep disorder

  • 30% ophthalmic disorders

  • fatigue

Non-specific dysmorphia   67%

Patients do not necessarily present with the distinctive morphological signs associated with this disease.

The portrait was drawn from the Face2gene research software.

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Explanation in pictures 

Socket  in Charge MYT1L

There is no specific treatment for this syndrome today.


  •  Treatment may take place depending on the clinical assessment established by the doctor in relation to certain repercussions of the syndrome.

  • Strict frameworks can be imposed with regard to dietetics, the practice of an adapted, sustained and regular sporting activity.

The multidisciplinary support must be put in place



Medical, medico-social support, rehabilitation 
regularly throughout life


  • In Liberal

  • In CAMPS (Early Medico-Social Action Center) - french medico-social model

  • In Hospital:   Autism Resource Center, Center for Neurodevelopmental Disorders...

  • In a Medico-Psychological Center, in the Medico-Psychological and Pedagogical Center i(french medico-social model)

  • At the place of education or at home via a SESSAD for example in french medico-social model

Support covered by social security in France

Accompaniments not covered by social security in France

  • Neuropediatrician / pediatrician

  • endocrinologist

  • Geneticist

  • Ophthalmologist / Orthoptist

  • ENT

  • Psychiatrist

  • Physiotherapist

  • Speech Therapist

  • Neurologist

  • Physician specializing in sleep disorders

  • Physician specializing in eating disorders...

  • Neuropsychologist

  • Psychomotrician

  • Occupational therapist

  • Psychologist

  • Special educator

  • Nutritionist

  • Osteopath...

!!!  As part of your procedures with the MDPH, you can obtain partial financial assistance for these expenses.

The paths

The paths are very varied, reflecting the heterogeneity of pathology profiles.

There is no single solution.

The devices are multiple and depend on:

  • the profile and needs of each patient

  • family resources (time, finances, mobility, etc.)

  • access to care and social assistance

  • medical prescriptions

  • decisions of the MDPH (Departmental House for the Disabled) in France

There is little information on adult patients.

Several situations were described to us: some are pursuing professional studies; others are in accompanied autonomy; some work part-time; and for others autonomy is not an option. 

Schooling in a specialized environment

  • Medical-Pedagogical Institute (IMP)

  • Medical-Educational Institute (IME)

  • Medical-Professional Institute (IMPro)

  • EEAP (Establishments and Services for children and adolescents with multiple disabilities)

  • ​ Day hospital

From 3 to 20 years old

Schooling in Ordinary Environment

  • In regular class

  • In Specialized device ULIS 

  • with or without additional human assistance to collective AESH

  • the intervention of a SESSAD

  • suitable equipment


    Elementary education,

   college and high school

Education at home

Over more or less long periods​

In coordination with the National Education services


MYT1L Patients

in the world

Thanks to the FB groups " Chromosome 2P25/ MYT1L Family Page " and " Les Extra-vaillants MYT1L ", and the generosity of the families, we were able to collect anonymous data which allows us to have a world view of the patients and their profile.


- X 2 between 2022 & 2023

- X 3,7 between 2021 & 2023

UPDATE APRIL 2022 vs October 2021

- + 40%  of patients identified World

- + 51% of patients identified Europe

- + 85% of patients identified France

These data were processed anonymously.

They offer an interesting vision, but much lower than the reality of the diagnoses.

Find the April 2022 update , and the complete file to October 2021 .

(click on the underlined words)

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