title: Ataxia-telangiectasia presenting with a novel immunodeficiency.
abstract: Ataxia-telangiectasia is a rare autosomal recessive disorder characterized by progressive cerebellar ataxia, oculocutaneous telangiectasias, and variable degrees of immunodeficiency. Immunologic evaluations of affected patients often reveal anomalies of humoral and cell-mediated immunity. We describe a case of ataxia-telangiectasia with an atypical immunodeficiency and a novel mutation in the ATM gene. The patient presented at age 3 years with a perineal cellulitis associated with profound neutropenia and T-cell lymphopenia. Serum immunoglobulin levels and antibody titers were normal. Neurologic evaluation revealed minimal hypotonia and wide-based gait, without other signs of cerebellar dysfunction. The alpha-fetoprotein level was elevated, and molecular genetic testing confirmed the diagnosis of ataxia-telangiectasia, uncovering a novel ATM gene mutation c.3931C>T (p.Gln1311X) in exon 28. This patient presents a unique immunologic pattern with normal immunoglobulin levels, significant lymphopenia, and profound neutropenia. The diagnosis of ataxia-telangiectasia should be considered in children presenting with gait disorder and immunologic defects, regardless of subtype and severity.
authors.affiliation: Division of Neurology, Department of Pediatrics, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Quebec, Canada. s.perreault@umontreal.ca
authors.forename: Sébastien
authors.initials: S
authors.lastname: Perreault
authors.forename: Geneviève
authors.initials: G
authors.lastname: Bernard
authors.forename: Anne
authors.initials: A
authors.lastname: Lortie
authors.forename: Françoise
authors.initials: F
authors.lastname: Le Deist
authors.forename: Hélène
authors.initials: H
authors.lastname: Decaluwe
mesh_terms: D001260:Ataxia Telangiectasia / Q000150:complications / Q000175:diagnosis* / Q000276:immunology; D002481:Cellulitis / Q000150:complications; D002675:Child, Preschool; D005500:Follow-Up Studies; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000503:physiopathology*; D008297:Male; D014555:Urination Disorders / Q000150:complications