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Genotype/phenotype correlations in two patients with 12q subtelomere deletions
Author(s) -
Niyazov Dmitriy M.,
Nawaz Zafar,
Justice April N.,
Toriello Helga V.,
Martin Christa Lese,
Adam Margaret P.
Publication year - 2007
Publication title -
american journal of medical genetics part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.064
H-Index - 112
eISSN - 1552-4833
pISSN - 1552-4825
DOI - 10.1002/ajmg.a.32005
Subject(s) - subtelomere , clinodactyly , phenotype , short stature , genetics , genotype , intellectual disability , medicine , biology , chromosome , gene
Subtelomeric imbalances have been implicated in developmental delay and mental retardation (MR) and described for most chromosomes. This study reports the first detailed description of two individuals with de novo 12q subtelomere deletions and high‐resolution mapping of their deletion size with oligonucleotide array CGH for genotype/phenotype comparisons. Patient 1 is an 8‐year‐old male with borderline mild MR, food‐seeking behavior, obesity, no significant dysmorphic facial features, abnormal hair whorl pattern, brachydactyly and mild clinodactyly. Patient 2 is a 12‐year‐old male with mild MR, food‐seeking behavior, obesity, short stature, mild dysmorphic facial features, multicystic kidney and unilateral cryptorchidism. Both patients share a deleted region of ∼1.6 Mb, including 14 known genes, which perhaps contributed to their similar phenotypes. However, Patient 2 has more severe MR and organ system involvement, possibly due to the larger deletion size (∼4.5 Mb) including an additional eight genes, although it is difficult to make phenotype/genotype correlations based on only two patients. Due to the relatively mild presentation of both of our patients, we propose that a proportion of individuals with subtelomeric imbalances may go undetected and therefore, recommend subtelomeric studies be carried out for cases of unexplained mild MR or isolated learning disability (LD) with behavioral problems in the absence of major dysmorphic features or birth defects. In addition, 12q subtelomeric deletions should be considered in the differential diagnosis of patients presenting with food‐seeking behavior and resultant obesity, as well as those referred to rule out Prader–Willi syndrome. © 2007 Wiley‐Liss, Inc.