Molecular cytogenetic characterization of an interstitial deletion of chromosome 21 (21q22.13q22.3) in a patient with dysmorphic features, intellectual disability and severe generalized epilepsy.

[monosomy 21]

We report on a de novo interstitial deletion of chromosome 21 q in a patient presenting with characteristic facial features , intellectual disability , and epilepsy . The deletion extent was about 4 .9 Â Mb from position 37713441 bp (21 q 22 .13 ) to position 42665162 bp (21 q 22 .3 ) (NCBI 36 /hg 18 map ). Patients with partial monosomy 21 are quite rare ; this anomaly has been associated with a wide spectrum of clinical signs , ranging from very mild to quite severe phenotypes . This variability results from variability in the deleted regions , thus accurate molecular definition of the chromosomal breakpoints is necessary to make better genotype-phenotype correlations . We compared our patient 's phenotype with the few other patients reported in the literature and found to have similar deletion when analyzed by array CGH . The minimal overlapping region contains only two genes , DYRK 1 A and KCNJ 6 , which may play a major role in these patients ' phenotype .

Diseases
Validation

Diseases presenting "epilepsy" symptom

22q11.2 deletion syndrome

adrenomyeloneuropathy

alexander disease

canavan disease

classical phenylketonuria

cohen syndrome

cowden syndrome

familial hypocalciuric hypercalcemia

gm1 gangliosidosis

hereditary cerebral hemorrhage with amyloidosis

hirschsprung disease

homocystinuria without methylmalonic aciduria

kabuki syndrome

locked-in syndrome

lymphangioleiomyomatosis

monosomy 21

neonatal adrenoleukodystrophy

pendred syndrome

phenylketonuria

proteus syndrome

pyruvate dehydrogenase deficiency

sneddon syndrome

wolf-hirschhorn syndrome

zellweger syndrome

This symptom has already been validated