Presence of ATM protein and residual kinase activity correlates with the phenotype in ataxia-telangiectasia: a genotype-phenotype study.

Ataxia-telangiectasia (A-T) is an autosomal recessive neurodegenerative disorder with multisystem involvement and cancer predisposition, caused by mutations in the A-T mutated (ATM) gene. To study genotype-phenotype correlations, we evaluated the clinical and laboratory data of 51 genetically proven A-T patients, and additionally measured ATM protein expression and kinase activity. Patients without ATM kinase activity showed the classical phenotype.

Impaired avidity maturation after tetanus toxoid booster in children with Down syndrome.

Down syndrome children show a decreased avidity of the antibody response after tetanus toxoid booster vaccination at 9 years of age suggesting impaired memory B cell selection in the germinal center. Clinicians need to be aware of this ongoing subtle immunologic deficit in Down syndrome.