title: Microarray based analysis of an inherited terminal 3p26.3 deletion, containing only the CHL1 gene, from a normal father to his two affected children.
abstract: BACKGROUND
  terminal deletions of the distal portion of the short arm of chromosome 3 cause a rare contiguous gene disorder characterized by growth retardation, developmental delay, mental retardation, dysmorphisms, microcephaly and ptosis. The phenotype of individuals with deletions varies from normal to severe. It was suggested that a 1,5 Mb minimal terminal deletion including the two genes CRBN and CNTN4 is sufficient to cause the syndrome. In addition the CHL1 gene, mapping at 3p26.3 distally to CRBN and CNTN4, was proposed as candidate gene for a non specific mental retardation because of its high level of expression in the brain.
  
  
  RESULTS
  we describe two affected siblings in which array-CGH analysis disclosed an identical discontinuous terminal 3p26.3 deletion spanning less than 1 Mb. The deletion was transmitted from their normal father and included only the CHL1 gene. The two brothers present microcephaly, light mental retardation, learning and language difficulties but not the typical phenotype manifestations described in 3p- syndrome.
  
  
  CONCLUSIONS
  a terminal 3p26.3 deletion including only the CHL1 gene is a very rare finding previously reported only in one family. The phenotype of the affected individuals in the two families is very similar and the deletion has been inherited from an apparently normal parent. As already described for others recurrent syndromes with variable phenotype, these findings are challenging in genetic counselling because of an evident variable penetrance.
authors: Laboratorio di Citogenetica, Istituto G. Gaslini, 16147 Genova, Italy.
authors: Cristina
authors: C
authors: Cuoco
authors: Patrizia
authors: P
authors: Ronchetto
authors: Stefania
authors: S
authors: Gimelli
authors: Frédérique
authors: F
authors: Béna
authors: Maria Teresa
authors: MT
authors: Divizia
authors: Margherita
authors: M
authors: Lerone
authors: Marisol
authors: M
authors: Mirabelli-Badenier
authors: Monica
authors: M
authors: Mascaretti
authors: Giorgio
authors: G
authors: Gimelli
mesh_terms: D015815:Cell Adhesion Molecules; D002648:Child; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics*; D005220:Fathers; D006130:Growth Disorders / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008831:Microcephaly / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D035781:Siblings
chemical_list: C490650:CHL1 protein, human; D015815:Cell Adhesion Molecules; D008565:Membrane Proteins