Characterization and Contribution of Genome-wide DNA Methylation (DNA Methylation Episignatures) in Rare Diseases With Prenatal Onset

Inclusion Criteria: * Patient Inclusion Criteria: * Fetuses with a postmortem examination as part of the etiological diagnosis of developmental abnormality within the Genomic Medicine of Rare Diseases department of the Necker Children's Hospital, and whose DNA extracted from lung and amniotic fluid is available * OR a child cared for in the Genomic Medicine for Rare Diseases department of the Necker Children's Hospital, and whose DNA extracted from whole blood is available * with pathogenic or probably pathogenic variation in a gene following CHD7, KMT2D, HYLS1, TCTN3 or FLVCR2 * whose parents have consented to molecular genetic testing as part of diagnosis and research * Negative Controls : * Fetuses with a postmortem examination as part of the etiological diagnosis of developmental abnormality within the Genomic Medicine of Rare Diseases department of the Necker Children's Hospital, and whose DNA extracted from lung and amniotic fluid are available * OR a child cared for in the Genomic Medicine for Rare Diseases department of the Necker Children's Hospital, and whose DNA extracted from whole blood is available * does not have pathogenic or probably pathogenic variation in a gene following CHD7, KMT2D, HYLS1, TCTN3 or FLVCR2 * whose parents have consented to molecular genetic testing as part of diagnosis and research * For everyone: • For living participants: Non-objection by holders of parental authority to the reuse of clinical data and biological samples collected and stored in the context of care (consent of care). • For deceased participants: * Consent of the holders of parental authority to the use of the samples kept for research purposes, signed as part of the treatment * No mention of opposition to the reuse of clinical data from the treatment in the patient's medical record Exclusion Criteria: * Refusal of postmortem examination in case of fetal loss * Parents' refusal of molecular investigations