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Table 1 Cases of interstitial duplications in chromosome region 6q21-6q23

From: Interstitial 6q21q23 duplication - variant of variable phenotype and incomplete penetrance or benign duplication?

  Cytogenetic results Molecular testing Minimal duplication region according to molecular tests Molecular breakpointsain GRCh37/hg19 Phenotype of the proband
Temple et al. 1996 46,XX, der(2) ins(2;6)(2pter-2p22.2::6q?22.32- ?6q?23.1::2p22.2–2qter)patb Markers analysis dup(6)(q23.3q24.1) (between markers D6S292 and D6S308) chr6: 136315214-141256931 small at birth, neonatal diabetes, microcephaly, myoclonic seizures, no DD (the insertion is resulting in partial trisomy: dup(6)(6q22.33–q23.3))
Arthur et al. 1997 46,XX, inv dup(6)(q22q23)pat Markers analysis invdup(6) (q23.2q24.1) (between markers D6S270 and D6S310 chr6: 134654821- 142102601 transient neonatal diabetes mellitus, minor dysmorphic features
Henegariu et al.1997 46,XX,dir dup(6) (q23.3q25.3)c FISH with painting probe for chr6 ukn ukn dolichocephaly, dyspmorphic features, long fingers, bilateral single palmar creases, contractures at the wrists, long fingers, dorsiflexion of the first toes, mild syndactyly of toes 2–3, bradycardia, mild tricuspid insufficiency, a small patent ductus arteriosus, and small atrial septal defect, moderate cardiomegaly, short neck but not webbed, umbilical hernia, and mild generalized hypertonia
Pratt et al. 1998 (2 cases) Case 1: 46,XY,dup(6)(q21q23.3)dn Case 2: 46,XX,dup(6)(q21.15q23.3)dn FISH with painting probe for chr6 ukn ukn Case 1: dysmorphic features, bilateral clubfoot, ulnar deviation of hands, decreased muscle tone, decreased subcutaneous fat, brain anomalies, a thickened tricuspid valve, bilateral transverse palmar creases, ulnar deviation of the hands, club feet, and small hands and feet Case 2: DD/ID (IQ 63), attention deficit disorder with hyperactivity, and coördination difficulties. Dysmorphic features, ventricular septal defect and pulmonic valvular stenosis, clinodactyly of the 5th finger, and thickened nails of the 5th toes, increased reflexes and ankle clonus.
Zneimer et al. 1998 46,XX,dup(6)(q21q23)dn FISH with painting probe for chr6 ukn Possibly dup(6)(q22q24) ivm neonatal diabetes mellitusd ukn born with umbilical hernia and transient insulin dependent diabetes until 7 months, delayed development and speech (receives speech therapy), dysmorphic features, cardiomegaly of unknown etiology
Goh et al. 2000 der(7)ins(7;6)(q21.11;q22.1q23.3)mat resulting in partial trisomy of 6q22.1q23.3 N.D. ukn ukn Case 1: obesity, brachycephaly, dysmorphic features, bilateral clinodactyly, DD, ID with IQ of 50.8, obstructive sleep apnoea Case 2: (older sister of case 1) brachycephaly, dysmorphic features, bilateral clinodactyly, mild DD, no formal IQ test, but left school without academic credits.
Causio et al. 2001 46, XY, dup(6)(q23q23)dn FISH with YAC probes dup(6)(q23.2q24.1) according to minimal duplication breakpoints using YAC probes (970A12-949D3) chr6: 132138813-142077202 plagiocephaly, DD, ID, hiatus hernia (corrected surgically), acrocephaly, dysmorphic features, short hands with clinodactyly of fifth finger, joint contractures. Nuclear cataract in OD and rotating nystagmus in OO, bicuspid aortic valve with moderate failure, psychotic behavior and neurological tics.
Pazooki et al. 2007 (mother and child) 46,XXdup(6)(q21q22.1)mat FISH with BAC probes dup(6)(q21q22.1) according to minimal breakpoints using BAC probes (RP11-428 F8 and RP1-64I15) chr6: 111498415- 116048892 Child: DD, stridor, nutritional problems, obesity, intention tremor, dysmorphic features (anteverted nares, depressed nasal bridge, hypertelorism, short fingers).
Mother: cognitive difficulties, obesity, intermittent tremor.
ISCA nssv 1495729 arr[hg19] 6q22.1q22.32(117,928,310-127,021,125)x3dn Oligo aCGH dup(6) (q22.1q22.32) chr6: 117928310-127021125 DD and/or other significant developmental or morphological phenotypes
Current family 1 arr[hg19] 6q22.1q23.2(116,411,005-132,541,408)x3mat Illumina Human CytoSNP-12 dup(6)(q22.1q23.2) chr6: 116411005-132541408 -normal phenotype in 6q duplication carriers, -variable phenotype (from learning problem to developmental delay and intellectual disability) in carriers of both 6q duplication and 16p11.2 microduplication.
Current family 2 arr[hg19] 6q21q22.33(113,464,340-128,801,386)x3mat Affymetrix SNP CytoScan HD dup(6)(q21q22.33) chr6: 113464340-128801386 Fetus: dysmorphic features (anteverted nares, short nose, long eyelashes), esophageal atresia, pulmonary lobulation anomaly, meckel diverticulum, bilateral hydronephrosis, pancreatic ectopia, neuronal heterotopia of the cerebellum (dentate nucleus). Termination of pregnancy at 33WG.
arr[hg19] 6q21q22.33(113,465,762-128,774,807)x3dn Oligo aCGH Agilent 60 K dup(6)(q21q22.33) chr6: 113465762-128774807 Mother: learning difficulties, dyslexia, scoliosis.
  1. N.D. not done, dn de novo, mat maternal, pat paternal, DD developmental delay, ID intellectual disability, ukn unknown
  2. aThe molecular breakpoint were either given by the authors or translated from molecular markers/FISH probes and show minimal region of imbalance
  3. b Father and grandfather had duplicated 6q, but no abnormal features or neonatal diabetes
  4. c Not maternal, father not tested, if including band 6q24 probably de novo on maternal chromosome as neonatal diabetes mellitus was not stated
  5. d The work of Docherty and colleagues proved that neonatal diabetes mellitus is associated with 6q24 (Docherty, Poole et al. 2010), it may be assumed that the actual duplicated region does not contain bands q21q23, but more distal region on the long arm of chromosome 6 including 6q22q24