title: Survival of male patients with incontinentia pigmenti carrying a lethal mutation can be explained by somatic mosaicism or Klinefelter syndrome.
abstract: Incontinentia pigmenti (IP), or "Bloch-Sulzberger syndrome," is an X-linked dominant disorder characterized by abnormalities of skin, teeth, hair, and eyes; skewed X-inactivation; and recurrent miscarriages of male fetuses. IP results from mutations in the gene for NF-kappaB essential modulator (NEMO), with deletion of exons 4-10 of NEMO accounting for >80% of new mutations. Male fetuses inheriting this mutation and other "null" mutations of NEMO usually die in utero. Less deleterious mutations can result in survival of males subjects, but with ectodermal dysplasia and immunodeficiency. Male patients with skin, dental, and ocular abnormalities typical of those seen in female patients with IP (without immunodeficiency) are rare. We investigated four male patients with clinical hallmarks of IP. All four were found to carry the deletion normally associated with male lethality in utero. Survival in one patient is explained by a 47,XXY karyotype and skewed X inactivation. Three other patients possess a normal 46,XY karyotype. We demonstrate that these patients have both wild-type and deleted copies of the NEMO gene and are therefore mosaic for the common mutation. Therefore, the repeat-mediated rearrangement leading to the common deletion does not require meiotic division. Hypomorphic alleles, a 47,XXY karyotype, and somatic mosaicism therefore represent three mechanisms for survival of males carrying a NEMO mutation.
authors.affiliation: Addenbrooke's Hospital, Cambridge, UK. SJK12@mole.bio.cam.ac.uk
authors.forename: S
authors.initials: S
authors.lastname: Kenwrick
authors.forename: H
authors.initials: H
authors.lastname: Woffendin
authors.forename: T
authors.initials: T
authors.lastname: Jakins
authors.forename: S G
authors.initials: SG
authors.lastname: Shuttleworth
authors.forename: E
authors.initials: E
authors.lastname: Mayer
authors.forename: L
authors.initials: L
authors.lastname: Greenhalgh
authors.forename: J
authors.initials: J
authors.lastname: Whittaker
authors.forename: S
authors.initials: S
authors.lastname: Rugolotto
authors.forename: T
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authors.lastname: Bardaro
authors.forename: T
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authors.lastname: Esposito
authors.forename: M
authors.initials: M
authors.lastname: D'Urso
authors.forename: F
authors.initials: F
authors.lastname: Soli
authors.forename: A
authors.initials: A
authors.lastname: Turco
authors.forename: A
authors.initials: A
authors.lastname: Smahi
authors.forename: D
authors.initials: D
authors.lastname: Hamel-Teillac
authors.forename: S
authors.initials: S
authors.lastname: Lyonnet
authors.forename: J P
authors.initials: JP
authors.lastname: Bonnefont
authors.forename: A
authors.initials: A
authors.lastname: Munnich
authors.forename: S
authors.initials: S
authors.lastname: Aradhya
authors.forename: C D
authors.initials: CD
authors.lastname: Kashork
authors.forename: L G
authors.initials: LG
authors.lastname: Shaffer
authors.forename: D L
authors.initials: DL
authors.lastname: Nelson
authors.forename: M
authors.initials: M
authors.lastname: Levy
authors.forename: R A
authors.initials: RA
authors.lastname: Lewis
mesh_terms: D000483:Alleles; D002648:Child; D002675:Child, Preschool; D004303:Dosage Compensation, Genetic; D005260:Female; D005804:Genes, Lethal / Q000235:genetics*; D006801:Humans; D051550:I-kappa B Kinase; D007184:Incontinentia Pigmenti / Q000235:genetics* / Q000473:pathology; D007223:Infant; D007231:Infant, Newborn; D007621:Karyotyping; D007713:Klinefelter Syndrome / Q000235:genetics*; D008297:Male; D008540:Meiosis / Q000235:genetics; D009030:Mosaicism / Q000235:genetics*; D010375:Pedigree; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D017384:Sequence Deletion / Q000235:genetics*; D015996:Survival Rate
chemical_list: D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human