Revision of "A 223-kb de novo deletion of PAX9 in a patient with oligodontia".

The PAX (paired box) genes are a family of transcription factors critical for fetal growth and organogenesis. Abnormalities of PAX2, PAX3, PAX6, and PAX9 are associated with various congenital craniofacial anomalies, including tooth abnormalities. We present here a boy with oligodontia. Dental radiographs showed that he lacked primary molars and was missing most of his permanent teeth. A genome-wide single-nucleotide polymorphism-based microarray revealed a de novo 223-kb heterozygous deletion on 14q13.3 that included the PAX9 gene. The findings in this patient illustrate the role of the PAX9 gene in tooth development and provide the first example of a de novo deletion of 14q13.3 manifesting primarily with oligodontia. This report also supports the utility of genome-wide microarrays in determining the genetic cause of craniofacial abnormalities.

A 223-kb de novo deletion of PAX9 in a patient with oligodontia.

The PAX (paired box) genes are a family of transcription factors critical for fetal growth and organogenesis. Abnormalities of PAX2, PAX3, PAX6, and PAX9 are associated with various congenital craniofacial anomalies, including tooth abnormalities. We present here a boy with oligodontia and language delay. Dental x-rays showed that he lacked primary molars and was missing most of his permanent teeth. A genome-wide, single-nucleotide polymorphism-based microarray revealed a de novo 223-kb heterozygous deletion on 14q13.3 that included the PAX9 gene. In addition, the array showed 2 copies of the X chromosome and 1 copy of the Y chromosome, diagnostic for Klinefelter syndrome. The findings in this patient illustrate the role of the PAX9 gene in tooth development and provide the first example of a de novo deletion of 14q13.3 manifesting primarily with oligodontia. This report also supports the utility of genome-wide microarrays in determining the genetic cause of craniofacial abnormalities.

A recurrent 16p12.1 microdeletion supports a two-hit model for severe developmental delay.

We report the identification of a recurrent, 520-kb 16p12.1 microdeletion associated with childhood developmental delay. The microdeletion was detected in 20 of 11,873 cases compared with 2 of 8,540 controls (P = 0.0009, OR = 7.2) and replicated in a second series of 22 of 9,254 cases compared with 6 of 6,299 controls (P = 0.028, OR = 2.5). Most deletions were inherited, with carrier parents likely to manifest neuropsychiatric phenotypes compared to non-carrier parents (P = 0.037, OR = 6). Probands were more likely to carry an additional large copy-number variant when compared to matched controls (10 of 42 cases, P = 5.7 x 10(-5), OR = 6.6). The clinical features of individuals with two mutations were distinct from and/or more severe than those of individuals carrying only the co-occurring mutation. Our data support a two-hit model in which the 16p12.1 microdeletion both predisposes to neuropsychiatric phenotypes as a single event and exacerbates neurodevelopmental phenotypes in association with other large deletions or duplications. Analysis of other microdeletions with variable expressivity indicates that this two-hit model might be more generally applicable to neuropsychiatric disease.

The role of osteopontin in the development of albuminuria.

Several gene array studies have suggested that osteopontin (Opn) expression strongly correlates with albuminuria and glomerular disease. Urinary Opn concentration and kidney Opn immunoreactivity were found to be increased in patients with steroid-sensitive nephrotic syndrome. In addition, renal Opn mRNA was increased in the Ins2(Akita) mouse model of type 1 diabetic nephropathy, in the LPS-induced albuminuria model, and in glomeruli of puromycin aminonucleotide-induced nephrotic rats. Opn knockout mice did not develop albuminuria in response to LPS injection, and Opn knockout mice were protected from diabetes-induced albuminuria and mesangial expansion. In the glomerulus, Opn immunostaining was increased specifically in podocytes. Treatment of podocytes with recombinant Opn activated the NF-kappaB pathway, increased expression of urokinase plasminogen activator and matrix metalloproteinases 2 and 9, and increased podocyte motility. Taken together, these results indicate that Opn plays an important role in the development of albuminuria, possibly by modulating podocyte signaling and motility.

Poly(ADP-ribose) polymerase inhibitors ameliorate nephropathy of type 2 diabetic Leprdb/db mice.

The activation of the poly(ADP-ribose) polymerase (PARP) plays an important role in the pathophysiology of various diseases associated with oxidative stress. We found increased amounts of poly(ADP) ribosylated proteins in diabetic kidneys of Lepr(db/db) (BKsJ) mice, suggesting increased PARP activity. Therefore, we examined the effects of two structurally unrelated PARP inhibitors (INO-1001 and PJ-34) on the development of diabetic nephropathy of Lepr(db/db) (BKsJ) mice, an experimental model of type 2 diabetes. INO-1001 and PJ-34 were administered in the drinking water to Lepr(db/db) mice. Both INO-1001 and PJ-34 treatment ameliorated diabetes-induced albumin excretion and mesangial expansion, which are hallmarks of diabetic nephropathy. PARP inhibitors decreased diabetes-induced podocyte depletion in vivo and blocked hyperglycemia-induced podocyte apoptosis in vitro. High glucose treatment of podocytes in vitro led to an early increase of poly(ADP) ribosylated modified protein levels. Reactive oxygen species (ROS) generation appears to be a downstream target of hyperglycemia-induced PARP activation, as PARP inhibitors blocked the hyperglycemia-induced ROS generation in podocytes. INO-1001 and PJ-34 also normalized the hyperglycemia-induced mitochondrial depolarization. PARP blockade by INO-1001 and PJ-34 prevented hyperglycemia-induced nuclear factor-kappaB (NFkappaB) activation of podocytes, and it was made evident by the inhibitor of kappaBalpha phosphorylation and NFkappaB p50 nuclear translocation. Our results indicate that hyperglycemia-induced PARP activation plays an important role in the pathogenesis of glomerulopathy associated with type 2 diabetes and could serve as a novel therapeutic target.