title: The spectrum of parathyroid gland dysfunction associated with the microdeletion 22q11.
abstract: OBJECTIVE
  Clinical features associated with microdeletion of chromosome 22q11 (del(22)(q11)) are highly variable. Increased awareness of this condition is needed among specialists such as endocrinologists to reduce diagnostic delay and improve clinical care. The purpose of this study was to describe the phenotype of patients with del(22)(q11), focusing on parathyroid gland dysfunction.
  
  
  METHODS
  Charts of 19 patients, including one kindred of three, known to have del(22)(q11) diagnosed by fluorescence in situ hybridization (FISH) were reviewed from the register of the department of Medical Genetics. Major clinical features including hypoparathyroidism phenotype were collected.
  
  
  RESULTS
  Parathyroid dysfunction was present in 8 out of 16 patients (50%). Six patients were diagnosed with overt hypoparathyroidism. Hypocalcemia manifested as laryngeal stridor within the first days of life (n = 3), seizures in infancy (n = 1) and adolescence (n = 2). The connection between hypoparathyroidism and diagnosis of del(22)(q11) was belated at the median age of 18 years. One patient had presented with transient neonatal hypoparathyroidism, and one patient had latent hypoparathyroidism. Within the kindred family, the phenotype variability including that of parathyroid dysfunction was as marked as between unrelated individuals. Standard karyotype failed to detect the deletion in 15 out of 19 cases.
  
  
  CONCLUSIONS
  Abnormal parathyroid function in the del(22)(q11) ranges from severe neonatal hypocalcemia to latent hypoparathyroidism. Del(22)(q11) should be considered as a potential cause of hypocalcemia even in young adult. When suspected, the diagnosis requires investigation by FISH. Furthermore, long-term calcemia follow-up is needed in normocalcemic patients with del(22)(q11) because of the possible evolution to hypocalcemic hypoparathyroidism.
authors.affiliation: Department of Endocrinology and Reproductive Medecine, Nice University Hospital, BP 3079, 06202 Nice cedex 3, France. hieronimus.s@chu-nice.fr
authors.forename: Sylvie
authors.initials: S
authors.lastname: Hiéronimus
authors.forename: Magali
authors.initials: M
authors.lastname: Bec-Roche
authors.forename: Florence
authors.initials: F
authors.lastname: Pedeutour
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Lambert
authors.forename: Kathy
authors.initials: K
authors.lastname: Wagner-Malher
authors.forename: Jean Christophe
authors.initials: JC
authors.lastname: Mas
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Sadoul
authors.forename: Patrick
authors.initials: P
authors.lastname: Fénichel
mesh_terms: D000293:Adolescent; D000328:Adult; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D006801:Humans; D006996:Hypocalcemia / Q000097:blood / Q000209:etiology; D007011:Hypoparathyroidism / Q000209:etiology / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D010279:Parathyroid Diseases / Q000097:blood / Q000235:genetics* / Q000503:physiopathology; D010281:Parathyroid Hormone / Q000097:blood; D010641:Phenotype; D012189:Retrospective Studies; D012640:Seizures / Q000209:etiology / Q000235:genetics
chemical_list: D010281:Parathyroid Hormone