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Two unrelated children with overlapping 6q25.3 deletions, motor speech disorders, and language delays
Author(s) -
Peter Beate,
Lancaster Hope,
Vose Caitlin,
Fares Amna,
Schrauwen Isabelle,
Huentelman Matthew
Publication year - 2017
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.38385
Subject(s) - hypotonia , dysarthria , speech delay , apraxia , language delay , corpus callosum , global developmental delay , genetics , psychology , audiology , medicine , phenotype , biology , neuroscience , gene , language development , aphasia , developmental psychology
Interstitial and terminal 6q25 deletions are associated with developmental delays, hypotonia, eye pathologies, craniofacial dysmorphologies, and structural brain anomalies. In most cases, speech and language deficits are not described in detail. We report on a case (Patient 1, age 7 years) with a de novo 6q25.3‐qter deletion, 11.1 Mb long and encompassing 108 genes, and a case (Patient 2, age 5 years) with an inherited interstitial 6q25.3 deletion, located within Patient 1's deletion region and 403 kb long, the smallest 6q25 deletion reported to date. Both children have hypotonia, motor speech disorders, and expressive language delays. Patient 1's speech was characterized by childhood apraxia of speech (CAS) and dysarthria. Other findings include developmental delay, ataxic cerebral palsy, optic nerve dysplagia, and atypical brain morphologies regarding the corpus callosum and gyration patterns, a clinical profile that closely matches a previously reported case with a nearly identical deletion. Patient 2 had speech characterized by CAS and typical nonverbal processing abilities. His father, a carrier, had typical speech and language but showed difficulties with complex motor speech and hand motor tasks, similar to other adults with residual signs of CAS. The small deletion in this family contains the IGF2R‐AIRN‐SLC22A2‐SLC22A3 gene cluster, which is associated with imprinting and maternal‐specific expression of Igf2R, Slc22a2, and Slc22a3 in mice, whereas imprinting in humans is a polymorphic trait. The shared phenotypes in the two patients might be associated with the deletion of the gene cluster.