Spectrum Mutations That Cause Hereditary Predisposition to Retinoblastoma

Mutational analysis in DNA from peripheral blood identifies predisposing RB1 gene mutations in almost all patients with familial retinoblastoma (>95%) and in most patients with sporadic bilateral retinoblastoma (>85%) (Refs. [14,15] and unpublished results).

• Large deletions. About 5-10% of patients with bilateral and almost 5% of patients with sporadic unilateral retinoblastoma have interstitial cytogenetic deletions involving 13q14.

• Gross deletions. This class of mutations includes deletions of one or more exons up to the loss of the whole RB1 gene. Recent studies indicate that gross deletions account for 10-20% of predisposing RB1 gene mutations. The location and size of these mutations are heterogeneous.[15]

• Point mutations. More than 70% of mutations that predispose to retinoblastoma are single-base substitutions and small-length mutations (database of RB1 gene mutations: http://www.d-lohmann.de/Rb/ mutations.html and Refs. [15,16]). Most of them are nonsense or frameshift alterations. Recurrent nonsense mutations are observed at 12 of the 15 CGA codons within the open reading frame. Missense mutations and small in-frame length alterations are infrequent (less than 10% of point mutations) and located in the regions that code for the pocket domains A and B of pRB.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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