title: [Ring chromosome 21. A new case].
mesh_terms: D002869:Chromosome Aberrations / Q000175:diagnosis*; D025063:Chromosome Disorders; D002904:Chromosomes, Human, 21-22 and Y; D005260:Female; D005817:Genetic Counseling; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D008297:Male; D011247:Pregnancy; D011296:Prenatal Diagnosis
vernacular_title: Chromosome 21 en anneau. A propos d'une nouvelle observation