Connexion

GENATLAS PHENOTYPE

last update : 19/03/07

Symbol	DEL7Q21
Location	7q21.3
Name	chromosome 7q21 interstitial deletion
Other name(s)	monosomy 7q21
Corresponding gene	SHFM1 , DLX5 , DLX6 , SGCE , KRIT1
Main clinical features	severe mental retardation, short stature, microcephaly inconstant limb abnormalities (split hand/split foot malformation) hearing loss in about one-third of these patients and genito-urinary abnormalities in some variable size and gene content may sustain a different phenotype
Genetic determination	chromosomal
Related entries	SHFM1
Function/system disorder	multisystem/generalized
	mental retardation
	osteo-articular
Type	MCA/MR

Mechanism(s)

Gene mutation	Chromosome rearrangement	Effect	Comments

	breakpoint		translocation or inversion with a breakpoint at 7q21.3
	deletion		interstitial, variable size with a ~1.2 Mb critical region containing the DLX5, DLX6 and DSS1 candidate genes
	deletion		ranging in size from 1.63 to 8.78 Mb encompassing up to 43 genes among which SGCE, KRIT, COL1A2 with/without SHFM1D, DLX5 and DLX6 ; gene content determines the clinical phenotype

Remark(s)

Genotype/Phenotype correlations

~30 percent of obligate carriers show no phenotypic abnormalities ; patients with paternal deletion encompassing the maternally imprinted gene SGCE have a myoclonus-dystonia plus syndrome (see DYT11) ; some deletions may include the KRIT gene, which is a major cause of cavernous cerebral malformations type I ; hearing loss, craniofacial defects, and an inv(7)(q21.3q35) with a 5 bp deletion at the 7q21.3 breakpoint that could contain regulatory elements necessary for DLX5 and DLX6 expression