Long QT syndrome in chromosome 7q35q36.3 deletion involving KCNH2 gene: Warning for chlorpheniramine prescription.

BACKGROUND: The deletion of the distal 7q region is a rare chromosomal syndrome characterized by wide phenotypic manifestations including growth and psychomotor delay, facial dysmorphisms, and genitourinary malformations. METHODS: We describe a 6-year-old child with a 12-Mb deletion of the region 7q35q36.3. RESULTS: Among the deleted genes, two genes have cardiac implications: PRKAG2 (OMIM #602743), associated with hypertrophic cardiomyopathy, cardiac conduction disease, and sudden death, and KCNH2 (OMIM #152427), coding for a cardiac potassium channel involved in long QT syndrome, unmasked by the chlorpheniramine treatment. At same time, the SHH gene (OMIM #600725), encoding sonic hedgehog, a secreted protein that is involved in the embryonic development, is deleted. CONCLUSION: Our report underlines potential cardiac complications linked to the common pharmacological treatment in this rare multiorgan and proteiform disease.

Clinical and molecular characterization of an emerging chromosome 22q13.31 microdeletion syndrome.

Microdeletion of chromosome 22q13.31 is a very rare condition. Fourteen patients have been annotated in public databases but, to date, a clinical comparison has not been done and, consequently, a specific phenotype has not been delineated yet. We describe a patient showing neurodevelopmental disorders, dysmorphic features, and multiple congenital anomalies in which SNP array analysis revealed an interstitial 3.15 Mb de novo microdeletion in the 22q13.31 region encompassing 21 RefSeq genes and seven non-coding microRNAs. To perform an accurate phenotype characterization, clinical features observed in previously reported cases of 22q13.31 microdeletions were reviewed and compared to those observed in our patient. To the best of our knowledge, this is the first time that a comparison between patients carrying overlapping 22q13.31 deletions has been done. This comparison allowed us to identify a distinct spectrum of clinical manifestations suggesting that patients with a de novo interstitial microdeletion involving 22q13.31 have an emerging syndrome characterized by developmental delay/intellectual disability, speech delay/language disorders, behavioral problems, hypotonia, urogenital, and hands/feet anomalies. The microdeletion identified in our patient is the smallest reported so far and, for this reason, useful to perform a detailed genotype-phenotype correlation. In particular, we propose the CELSR1, ATXN10, FBLN1, and UPK3A as candidate genes in the onset of the main clinical features of this contiguous gene syndrome. Thus, the patient reported here broadens our knowledge of the phenotypic consequences of 22q13.31 microdeletions facilitating genotype-phenotype correlations. Additional cases are needed to corroborate our hypothesis and confirm genotype-phenotype correlations of this emerging syndrome.

PARK2 Microduplication: Clinical and Molecular Characterization of a Further Case and Review of the Literature.

We report on a patient with psychomotor deficits, language delay, dyspraxia, skeletal anomalies, and facial dysmorphisms (hirsutism, right palpebral ptosis, a bulbous nasal tip with enlarged and anteverted nares, and a mild prominent antihelix stem). Using high-resolution SNP array analysis, we identified a 0.49-Mb microduplication in chromosome 6q26 inherited from the mother involving the PARK2 gene: arr[hg19] 6q26(162,672,821-163,163,143)×3 mat. To the best of our knowledge, this is the third patient to date described in whom a 6q26 microduplication encompassing only the PARK2 gene has been reported in medical literature. The PARK2 gene is a neurodevelopmental gene that was initially discovered as one of the causes of autosomal recessive juvenile Parkinson disease and subsequently reported to be linked to autism spectrum disorders and attention-deficit hyperactivity disorders. We provide an overview of the literature on PARK2 microduplications and further delineate the associated phenotype. Taken together, our findings confirm the involvement of this gene in neurodevelopmental disorders and are useful to strengthen the hypothesis that, although with variable expressivity and incomplete penetrance, the PARK2 microduplication is associated with a new emerging neurodevelopmental delay syndrome. However, clinical and molecular evaluations of more patients with the microduplication are needed for full delineation of this syndrome.