An anatomical study of a duplication 6p based on two sibs

Abstract

Dup (6p) patients have a peculiar facial appearance (frontal bossing, hypotelorism, hypoplastic midface), low birthweight, cardiovascular defects, small kidneys, and psychomotor retardation. We thought that a detailed anatomical dissection would more precisely define the syndrome, which has been developed from clinical evaluations and autopsy reports. Our patient, a female adolescent, died at 17 11/12 years and is the oldest patient with this syndrome to be described. The brain and skull showed the greatest number of abnormalities. The brain was smaller than normal and abnormally shaped. Many of the skull abnormalities, including shortened basisphenoid/basiocciput, reduced size of cranial fossae, and steep orbital roofs, may be attributed to the brain's shape. There were no olfactory bulbs, and only one rudimentary olfactory tract was present. Other findings were the following: a high interventricular septal defect and right ventricular hypertrophy, absence of uterus and vagina, hypoplastic ovaries, a common mesentery, two left extensor indicis bellies, bilateral absence of palmaris brevis and of peroneus tertius. Our results are compared with anomalies found in other aneuploidy syndromes. Variations in some organ systems may be similar to those whose presence Shapiro [1983] has attributed to amplified developmental instability. Relationships between the brain shape and size and skull abnormalities are also discussed. From 16 reported cases, a detailed autopsy report of the affected brother, and our anatomical findings, we suggest that this syndrome may also be characterized by arhinencephaly, common mesentery, absent uterus in the female, and growth retardation in those surviving the neonatal period.

Unbalanced 4;6 translocation and progressive renal disease

“…Autopsy results of one patient showed hypoplastic kidneys with only three calyces and subchronic glomerulonephritis [Breuning et al, 1977]. Other kidney variations including horseshoe kidney, an ectopic left kidney, and cystic abnormalities of Potter type III have been described [Smith and Pettersen, 1985;Fryns et al, 1986;Wauters et al, 1993]. Although small kidneys and/or proteinuria have been noted in approximately half of the patients, little is known about the underlying renal histopathology.…”

Karyotype-Phenotype Correlation in Partial Trisomies of the Short Arm of Chromosome 6: A Family Case Report and Review of the Literature

“…Characteristic craniofacial findings include craniosynostosis, prominent forehead, blepharophimosis and blepharoptosis, hypotelorism, low-set or malformed ears, small pointed chin, short and bulbous nose with tiny nares, choanal atresia, prominent nasal bridge, and small mouth with thin lips. Intellectual disability, epilepsy, mental retardation, autism, brain abnormalities, hearing loss, ocular defects, or immunodeficiency with susceptibility to pulmonar infections have also been reported [Smith and Pettersen, 1985;Fryns et al, 1986;Burd et al, 1988;Krassikoff and Sekhon, 1989;Katafuchi et al, 1992;Wauters et al, 1993;Giardino et al, 2002;Bart et al, 2011]. Furthermore, this chromosome anomaly is associated with a reduced life span [Villa et al, 2000;Stohler et al, 2007].…”

Partial 6p Trisomy with Abnormal ABR and Hypogenesis of the Corpus Callosum.

“…Another patient's height is only 119 cm at 17 years of age (Smith and Pettersen 1985). The features of this syndrome do not seem to depend on the chromosomal break points (Ferrando et al 1981;Scarbrough et al 1986;Burd et al 1988).…”

“…Central nervous sustem (CNS) disorders associated with 6p trisomy are hydrocephaly (Breuning et al 1977;Eden et al 1985;Scarbrough et al 1986), arhinencephaly (Pearson G 1979;Smith and Pettersen 1985), agenesis of the corpus callosum (Katafuchi et al 1992), and chronic meningitis (Therkelsen et al 1971;Breuning et al 1977). To our knowledge, previous cranial MRI of patients with 6p trisomy has been reported only in one case in which complete agenesis of the corpus callosum was revealed (Katafuchi et al 1992).…”