title: Three cases with de novo 6q imbalance and variable prenatal phenotype.
abstract: We describe two families in which three fetuses had a de novo 6q imbalance and abnormal phenotypes. We determined the boundaries and the parental origin of the chromosomal alterations by segregation analysis using a panel of short tandem repeats (STRs) located on 6q. Cases 1 and 2 (family A) were two sibs with 6q imbalance involving different regions. Case 1 was a female fetus with arthrogryposis, who had a complex rearrangement resulting in two deleted regions (6q22 and 6q25.1-q25.2) and a duplication of 6q23-q25.1. This latter imbalance was reported previously and is associated with joint contractures and short neck, also present in this fetus. The sib (case 2) had intrauterine growth restriction (IUGR) and agenesis of the ductus venosus. This male died shortly after birth; postnatal karyotype and molecular investigations showed a 6q21 de novo deletion. Case 3 (family B) had a prenatally detected deletion of 6q14-q16. Autopsy of the fetus documented minor facial anomalies and contractures of the limbs. All rearrangements were de novo and of paternal origin. Our data and the consistent number of cases of de novo 6q alterations previously reported suggest that chromosome arm 6q could be prone to rearrangements resulting in heterogeneous phenotypes. In family A, chromosome 6q imbalances involving different chromosomal regions were present in two consecutive pregnancies. In such cases counseling should suggest the impossibility of excluding recurrence of a chromosomal imbalance, and should discuss the option of early prenatal diagnosis in subsequent pregnancies.
authors.affiliation: Dipartimento di Medicina, Chirurgia ed Odontoiatria, Genetica Medica, Università degli Studi di Milano, Milano, Italia.
authors.forename: Francesca R
authors.initials: FR
authors.lastname: Grati
authors.forename: Faustina
authors.initials: F
authors.lastname: Lalatta
authors.forename: Licia
authors.initials: L
authors.lastname: Turolla
authors.forename: Ugo
authors.initials: U
authors.lastname: Cavallari
authors.forename: Barbara
authors.initials: B
authors.lastname: Gentilin
authors.forename: Franca
authors.initials: F
authors.lastname: Rossella
authors.forename: Irene
authors.initials: I
authors.lastname: Cetin
authors.forename: Patrizio
authors.initials: P
authors.lastname: Antonazzo
authors.forename: Maria
authors.initials: M
authors.lastname: Bellotti
authors.forename: Francesca
authors.initials: F
authors.lastname: Dulcetti
authors.forename: Demetrio
authors.initials: D
authors.lastname: Baldo
authors.forename: Romano
authors.initials: R
authors.lastname: Tenconi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Simoni
authors.forename: Monica
authors.initials: M
authors.lastname: Miozzo
mesh_terms: D002869:Chromosome Aberrations / Q000196:embryology; D002871:Chromosome Banding; D002872:Chromosome Deletion; D002896:Chromosomes, Human, Pair 6 / Q000235:genetics*; D017809:Fatal Outcome; D005260:Female; D005313:Fetal Death; D005333:Fetus / Q000002:abnormalities* / Q000378:metabolism; D006801:Humans; D007621:Karyotyping; D008297:Male; D018895:Microsatellite Repeats; D011247:Pregnancy; D011296:Prenatal Diagnosis