Journal of Medical Cases, ISSN 1923-4155 print, 1923-4163 online, Open Access
Article copyright, the authors; Journal compilation copyright, J Med Cases and Elmer Press Inc
Journal website

Case Report

Volume 6, Number 12, December 2015, pages 547-553

Contraction of a Maternal Fragile X Mental Retardation 1 Premutation Allele


Figure 1.
Figure 1. Pedigree of a family with an atypical transmission of the FMR1 allele over three generations. II-2 is the individual with a premutation allele of 109 CGG repeats which contracted in the following generation. The proband with a premutation allele identified through the NBS pilot project is indicated by an arrow. A dot within a square or a circle indicates that the corresponding individual has a premutation or intermediate allele.
Figure 2.
Figure 2. CGG size instability. Electrophoregrams (CE) illustrate the four cases including the grandmother with a premutation (II-2), the father carrier of an intermediate allele (III-2), and the two premutation daughters (IV-2 and IV-4). The electrophoregrams visualize the PCR amplicons obtained by triplet-primer PCR (TR-PCR) method as described in Sadic-Filipovik et al, 2010. The x-axis represents the size of the alleles in base pairs. The y-axis represents the fluorescence intensity. Southern Blot data are presented on the right side of the CE and show the presence of an expanded alleles in all four cases (lane 1 in a, b, c and d). M: 1 kb size marker. C: negative control, female normal. Southern blot analysis was conducted as described in Tassone et al [37].


Table 1. IV-4 - Developmental Assessment Results
Age (months)Mullen (age equivalent in months)Vineland-II
Gross motorVisual receptionFine motorReceptive languageExpressive languageEarly learning compositeReceptiveExpressiveWrittenCommunicationPersonalDomesticCommunityDaily living skillsInterpersonal relationsPlay and leisure timeCoping skillsSocializationGross motor skillsFine motor skillsMotor skillsAdaptive behavior composite
L: low; ML: moderately low; A: adequate; MH: moderately high; H: high.
36-45454135Above averageMHAAAAMHAAAAAAAAAA