J Med Cases

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 http://www.journalmc.org

Case Report

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

Contraction of a Maternal Fragile X Mental Retardation 1 Premutation Allele

Figures

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. 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

**Table 1.** IV-4 - Developmental Assessment Results
Age (months)	Mullen (age equivalent in months)						Vineland-II
Age (months)	Gross motor	Visual reception	Fine motor	Receptive language	Expressive language	Early learning composite	Receptive	Expressive	Written	Communication	Personal	Domestic	Community	Daily living skills	Interpersonal relations	Play and leisure time	Coping skills	Socialization	Gross motor skills	Fine motor skills	Motor skills	Adaptive behavior composite
L: low; ML: moderately low; A: adequate; MH: moderately high; H: high.
6	5	7	4	5	5	Average	ML	A	-	A	ML	-	-	ML	A	A	-	A	ML	A	ML	A
13	14	17	15	11	8	Average	A	A	-	A	A	A	ML	A	A	A	L	A	A	A	A	A
24	-	29	24	27	21	Average	H	A	-	MH	MH	A	A	A	A	A	A	A	A	A	A	A
30	33	34	30	33	32	Average	A	A	-	A	A	ML	A	A	A	A	ML	A	A	ML	A	A
36	-	45	45	41	35	Above average	MH	A	A	A	A	MH	A	A	A	A	A	A	A	A	A	A