A large X-chromosomal deletion is associated with microphthalmia with linear skin defects (MLS) and amelogenesis imperfecta (XAI).
A female patient is described with clinical symptoms of both microphthalmia with linear skin defects (MLS or MIDAS) and dental enamel defects, having an appearance compatible with X-linked amelogenesis imperfecta (XAI). Genomic DNA was purified from the patient's blood and semiquantitative multiplex PCR revealed a deletion encompassing the amelogenin gene (AMELX). Because MLS is also localized to Xp22, genomic DNA was subjected to array comparative genomic hybridization, and a large heterozygous deletion was identified. Histopathology of one primary and one permanent molar tooth showed abnormalities in the dental enamel layer, and a third tooth had unusually high microhardness measurements, possibly due to its ultrastructural anomalies as seen by scanning electron microscopy. This is the first report of a patient with both of these rare conditions, and the first description of the phenotype resulting from a deletion encompassing the entire AMELX gene. More than 50 additional genes were monosomic in this patient.
Hobson
Grace M
GM
Alfred I. DuPont Hospital for Children, Wilmington, Delaware, USA.
Gibson
Carolyn W
CW
Aragon
Melissa
M
Yuan
Zhi-an
ZA
Davis-Williams
Angelique
A
Banser
Linda
L
Kirkham
Jennifer
J
Brook
Alan H
AH
D000293:Adolescent; D000567:Amelogenesis Imperfecta / Q000150:complications* / Q000235:genetics*; D015519:Bone Density / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D041321:Chromosomes, Human, X / Q000235:genetics*; D004252:DNA Mutational Analysis; D003743:Dental Enamel / Q000473:pathology / Q000648:ultrastructure; D003804:Dentin / Q000378:metabolism; D005260:Female; D018628:Gene Dosage; D020022:Genetic Predisposition to Disease; D006244:Hardness; D006801:Humans; D008850:Microphthalmos / Q000150:complications* / Q000235:genetics*; D012868:Skin Abnormalities / Q000150:complications* / Q000235:genetics; D049951:X Chromosome Inactivation; D055815:Young Adult