Violeta Velkoska-Ivanova1, Ellen Casey1
1Australian Clinical Laboratories, Clayton, Melbourne
Trisomy 10p is a relatively well-characterized chromosomal abnormality that may occur through a variety of cytogenetic mechanisms including malsegregation of familial balanced translocation, duplication or supernumerary chromosome. However, cases of true complete trisomy 10p are rarely reported and are useful to further delineate the trisomy 10p syndrome.
We present a 15 year-old patient with IQ=50, profound developmental delay and additional minor abnormalities. His molecular karyotype showed a variable gain of DNA segments mapped to the short arm of chromosome 10 in 10%-15% of this patient’s genome. Additional studies were undertaken and parental molecular karyotyping followed. The proband’s final karyotype is:
mos 47,XY,+mar/46,XY.ish?r(10)(p15.1p11.1) (WCP10+,CEP10+,PTEN-).
arr 10p15.1p11.21(4,280,637-37,083,941)x2~3 dn
The mosaic pattern, together with the variable segmental copy number seen by microarray is consistent with a small supernumerary chromosome, most likely a ring. The mechanism of this ring formation and its interpretation with SnP microarray is discussed.
A three day -old term newborn with normal antenatal scan was referred for molecular karyotyping with hand and feet abnormalities, with three middle toes and second and third fingers missing bilaterally. The SnP microarray analysis has shown a male result with an approximately 0.43 megabase interstitial duplication of chromosome region 10q24.31q24.32. This duplication involves genes associated with Split Hand Split Foot Malformation 3 (SHFM3)- a contiguous gene syndrome of chromosome region 10q24 (OMIM#246560 http://www.omim.org/entry/246560 SHFM3).The rare condition and its phenotype will be discussed.