Co-occurrence of achondroplasia and Down syndrome: Genotype/phenotype association

• Published in: Birth defects research. A Clinical and molecular teratology Vol. 88; no. 4; p. 228
• Main Authors: de Azevedo Moreira, Lilia Maria, Matos, Marcos A, Schiper, Patricia P, Carvalho, Acácia F L, Gomes, Ivalda C, Rolemberg, José C, Ferreira de Lima, Renata L L, Toralles, Maria B P
• Format: Journal Article
• Language: English
• Published: United States 01.04.2010
• Subjects: Achondroplasia - complications; Achondroplasia - genetics; Achondroplasia - pathology; Amino Acid Substitution; Down Syndrome - complications; Down Syndrome - genetics; Down Syndrome - pathology; Down Syndrome - psychology; Genotype; Humans; Infant, Newborn; Karyotyping; Male; Maternal Age; Mutation, Missense; Paternal Age; Phenotype; Point Mutation; Receptor, Fibroblast Growth Factor, Type 3 - genetics
• ISSN: 1542-0760
• DOI: 10.1002/bdra.20653

This report describes the sixth case of an unusual association: Down syndrome with achondroplasia. It also analyzes the effects of both of these disorders on patient phenotype. A male infant was evaluated for Down syndrome. His appearance also suggested a diagnosis of achondroplasia. The child was evaluated by physical examination, radiography, cytogenetic study, and mutation analysis. Chromosome analysis showed a karyotype of 47,XY,+21 in all 30 cells analyzed. Radiographic examination showed typical findings of achondroplasia, such as disproportionately large skull, shortening of limb segments, and lumbar lordosis. FGFR3 screening showed a heterozygous G1138A mutation. The interaction of these two distinct genetic disorders in the same patient produces a phenotype typical of each syndrome with some overlapping signs. This case represents de novo origin of two disorders that both may be parental-age related.