Epstein Syndrome (Disorder) Clinical Trial
Official title:
Phenotypic and Genotypic Identification and Characterization of MYH9-related Constitutional Thrombocytopenia
The research involves the establishment of a cohort including as much as possible cases of
macrothrombocytopenia related to a "MYH9 syndrome" and the study of mutations and
polymorphisms of MYH9 gene in all these patients. As MYH9 syndrome is an autosomal dominant
disorder, patients should be heterozygous for a MYH9 gene mutation.
The main goal of our project is looking for correlations between genotype and phenotype. It
is planned to characterize the phenotype and genotype of a cohort of patients, including
family members that will be addressed during the study in order to better understand the
platelet disorder and improve the epidemiological knowledge of MYH9 syndrome. The data will
be recorded in a database.
Definition: Extended description of the protocol, including information not already
contained in other fields, such as comparison(s) studied. The patients that will participate
in the study will be suffering or suspected suffering from MYH9 syndrome.
The study of MYH9 gene will be proposed to the patients but also to both parents of the
propositi and other family members (children and adults), whether symptomatic or not. The
relatives who will be proved to be heterozygotes for a MYH9 mutation will be considered as
new cases and therefore included in the cohort of patients.
Four groups of controls (individuals who are not affected by a decrease in the platelet
count) will be constituted:
A1: controls for proplatelets production study A2: controls for platelet proteome study B:
controls for MYH9 gene analysis C: controls for leukocytes immunofluorescence study
Patients Patients will be included at the 6 sites of the national Reference Center for
Inherited Platelet Disorders (CRPP) after signing an informed consent form. During the visit
of inclusion (V1), data usually required for the diagnosis of MYH9 syndrome will be
collected: clinical examination, auditory and ocular check, blood tests including MYH9 gene
analysis, and search for proteinuria.
Among patients with a MYH9 mutation, a limited number will be recruited in a second step for
participating to specific studies focused on the consequences of MYH9 mutations on the
proplatelets production and the platelet proteome. The selected patients should be
representative of the different phenotypes of MYH9 syndrome. They should be adults and have
a platelet count above 50 G / L. A blood sample will be drawn for this purpose during a
second visit (V2).
An annual control will be offered at year 1, year 2 and year 3 after inclusion to all the
patients confirmed to have MYH9 syndrome (with MYH9 mutation). Each control will include:
clinical examination and record of bleeding episodes, if any, during the past year, blood
tests, search for proteinuria. The last control (end of the study) will also include
auditory and ocular tests.
Relatives The relatives will be included in the study after signing informed consent form
during an inclusion visit (VAP) at one of the 6 sites of CRPP. During the visit, a blood
sample will be drawn for platelet and MYH9 gene study.
Controls The controls will be included in the study after signing informed consent at 6
sites of the CRPP. During their inclusion visit (VT), a blood sample will be drawn for
platelet and MYH9 gene study.
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Observational Model: Cohort