RT Book, Section A1 Bissonnette, Bruno A1 Luginbuehl, Igor A1 Marciniak, Bruno A1 Dalens, Bernard J. SR Print(0) ID 58062223 T1 Allan-Herndon Syndrome T2 Syndromes: Rapid Recognition and Perioperative Implications YR 2006 FD 2006 PB The McGraw-Hill Companies PP New York, NY SN 9780071354554 LK accessanesthesiology.mhmedical.com/content.aspx?aid=58062223 RD 2024/04/20 AB Although most neonates and infants with this disorder appear to develop normally in the first few months of life, the presence of poor muscle tone most often already is present at birth. By age 6 months, hypotonia, inability to hold up the head, and severe muscle atrophy are detectable. Severe mental retardation is associated with multiple congenital anomalies.