The purpose of this study is to determine the safety and tolerance of an oral administration of methionine in the treatment of pulmonary alveolar proteinosis due to the double mutation Ala393Thr / Ser567Leu in the MARS gene. This disease is very severe and especially leads to chronic respiratory insufficiency. There is no curative treatment for this disease. The MARS gene encodes the methionine tRNA synthetase (MetRS). Mutations in this gene leads to a defect in MetRS function. In cultured mutated yeast, addition of methionine in culture medium restores MetRS function. Therefore, the investigators hypothesized that treatment of patients with methionine could have beneficial effects on the disease.

NCT03887169

Conditions

1. Pulmonary Alveolar Proteinosis
2. Mutation Ala393Thr of the MARS Gene
3. mutationSer567Leu of the MARS Gene

Interventions

1. Drug: Methionine
2. Drug: Vitamin B12, B9, B6, C supplementation
3. Diagnostic Test: Methionine/homocysteine Dosage
4. Diagnostic Test: Thoracic CT scan
5. Diagnostic Test: Abdominal and liver ultrasound.
6. Diagnostic Test: Brain MRI

MeSH:Pulmonary Alveolar Proteinosis

HPO:Intraalveolar phospholipid accumulation

The purpose of this study is to determine the safety and tolerance of an oral administration of methionine in the treatment of pulmonary alveolar proteinosis due to the double mutation Ala393Thr / Ser567Leu in the MARS gene. --- Ala393Thr ---

Inclusion Criteria: - Minor Patient with alveolar proteinosis by double mutation Ala393Thr and SER567LEU of the MARS gene, genetically proven. --- Ala393Thr ---

- Patient for which methionine can be administered orally or by enteral probe (Nasogastric or gastrostomy probe) - Signed Informed consent form by parents / legal guardian Exclusion Criteria: - Patient with alveolar proteinosis by other mutations of the MARS gene - Patient with alveolar proteinosis secondary to another etiology or without identified cause - Refusal to participate in the study - High blood pressure requiring drug treatment - Heart failure - Known hypersensitivity to one of the substances used or potentially used in the study: methionine, vitamins B6, B12, B9 and C - Pre-Hypermethioninemia (Methioninemia > + 2 DS of normal for age) whatever the cause Inclusion Criteria: - Minor Patient with alveolar proteinosis by double mutation Ala393Thr and SER567LEU of the MARS gene, genetically proven. --- Ala393Thr ---

- Patient for which methionine can be administered orally or by enteral probe (Nasogastric or gastrostomy probe) - Signed Informed consent form by parents / legal guardian Exclusion Criteria: - Patient with alveolar proteinosis by other mutations of the MARS gene - Patient with alveolar proteinosis secondary to another etiology or without identified cause - Refusal to participate in the study - High blood pressure requiring drug treatment - Heart failure - Known hypersensitivity to one of the substances used or potentially used in the study: methionine, vitamins B6, B12, B9 and C - Pre-Hypermethioninemia (Methioninemia > + 2 DS of normal for age) whatever the cause Pulmonary Alveolar Proteinosis Mutation Ala393Thr of the MARS Gene mutationSer567Leu of the MARS Gene Pulmonary Alveolar Proteinosis Pulmonary alveolar proteinosis (PAP) is a rare respiratory disorder. --- Ala393Thr ---