Partial duplication of 18q including a distal critical region for Edwards Syndrome in a patient with normal phenotype and oligoasthenospermia: case report.

Several authors have attempted to construct a phenotype map for duplications of different portions of chromosome 18 to identify a possible critical region (CR) for Edwards Syndrome. Partial duplications of 18q have been reported in the literature involving the distal CR in patients with some clinical features of Edwards Syndrome. Here, we describe a phenotypically normal male with a large duplication on chromosome 18 that involves the proposed distal CR. The lack of clinical features is remarkable, except for pathological semen analysis, which suggests that terminal 17.4 Mb of 18q do not contain the Edwards Syndrome CR. Alternatively, unknown modifier factors or undetected somatic mosaicism might cause incomplete penetrance of this duplication.

Submicroscopic duplication of the Wolf-Hirschhorn critical region with a 4p terminal deletion.

Chromosomal rearrangements in the short arm of chromosome 4 can result in 2 different clinical entities: Wolf-Hirschhorn syndrome (WHS), characterized by severe growth delay, mental retardation, microcephaly, 'Greek helmet' facies, and closure defects, or partial 4p trisomy, associated with multiple congenital anomalies, mental retardation, and facial dysmorphisms. We present clinical and laboratory findings in a patient who showed a small duplication in 4p16.3 associated with a subtle terminal deletion in the same chromosomal region. GTG-banding analyses, multiplex ligation-dependent probe amplification analyses, and studies by array-based comparative genomic hybridization were performed. The results of the analyses revealed a de novo 1.3 Mb deletion of the terminal 4p and a 1.1 Mb duplication in our patient, encompassing the WHS critical region. Interestingly, this unusual duplication/deletion rearrangement results in an intermediate phenotype that shares characteristics of the WHS and the 4p trisomy syndrome. The use of novel technologies in the genetic diagnosis leads to the description of new clinical syndromes; there is a growing list of microduplication syndromes. Therefore, we propose that overexpression of candidate genes in WHS (WHSC1, WHSC2 and LETM1) due to a duplication causes a clinical entity different to both the WHS and 4p trisomy syndrome.

Rare chromosomal complement of trisomy 21 in a boy conceived by IVF and cryopreservation.

This report describes a case of mosaic Down syndrome due to an unusual karyotype in a patient conceived by assisted reproductive techniques and cryopreservation. The chromosomal complement consists of two different cell lines, one predominantly trisomic with a derivative chromosome due to a Robertsonian translocation (21;21) and another carrying a ring chromosome 21. The present work analyses the different mechanisms that could have led to mosaicism.

[ARX mutations and mental retardation of unknown etiology: three new cases in Spain]. / Mutaciones en el gen ARX y retraso mental no filiado: tres nuevos casos en España.

INTRODUCTION: Mental retardation has an approximated prevalence of 2% in the general population and its most frequent cause is X-fragile syndrome. This genetic disorder predominantly affects males and it is mainly caused by the expansion of CGG in FMR1 gene. Recently has been demonstrated that mutations in a new called ARX gene (aristaless-related homeobox) can also cause a similar form of X linked mental retardation, as well as other neurological disorders (autism, Partington or West syndrome). The most frequent mutation that has been reported is the c.428_451 dup24, which comprises almost 60% of all described. It causes an expansion of a polyalanine tract of ARX protein. CASE REPORTS: We report three cases of mental retardation in two different families where the mutation in ARX gene c.428_451 dup24 was found while X-fragile syndrome screening was made. Personal and familiar history, phenotype and evolution are described. CONCLUSION: The molecular analysis of this mutation should be considered as a routine for the genetic diagnosis of mental retardation in males of nondrafted cause.

Mutaciones en el gen ARX y retraso mental no filiado: tres nuevos casos en España / Arx mutations and mental retardation of unknow etiology: Three new cases in Spain

Introducción. El retraso mental tiene una prevalencia aproximada del 2% en la población general, y la causa hereditaria más frecuente es el síndrome X frágil. Esta entidad afecta predominantemente a varones y está fundamentalmente causada por la expansión del triplete CGG en el gen FMR1. Recientemente, se ha demostrado que mutaciones en un nuevo gen llamado ARX (aristaless related homeobox) pueden ocasionar también una forma similar de retraso mental ligado al X, entreun amplio espectro de trastornos neurológicos relacionados (autismo, síndrome de Partington o síndrome de West, entre otros). La mutación más frecuentemente descrita, aproximadamente un 60% del total, es la duplicación de 24 pares de bases en el exón 2 (c.428_451 dup24), que produce una expansión de un tramo de polialanina en la proteína ARX. Casos clínicos.Se comunican tres casos de retraso mental no filiado, pertenecientes a dos familias distintas, en los que se halló la mutación en el gen ARX c.428_451 dup24 al realizar un estudio genético adicional al cribado de síndrome X frágil. Se describen los antecedentes personales y familiares, características fenotípicas y evolución de cada uno de ellos. Conclusión. El análisis molecular de dicha mutación debería considerarse de rutina para el diagnóstico genético de retraso mental en varones de causa no filiada

Introduction. Mental retardation has an approximated prevalence of 2% in the general population and its mostfrequent cause is X-fragile syndrome. This genetic disorder predominantly affects males and it is mainly caused by the expansion of CGG in FMR1 gene. Recently has been demonstrated that mutations in a new called ARX gene (aristalessrelated homeobox) can also cause a similar form of X linked mental retardation, as well as other neurological disorders (autism, Partington or West syndrome). The most frequent mutation that has been reported is the c.428_451 dup24, which comprises almost 60% of all described. It causes an expansion of a polyalanine tract of ARX protein. Case reports. We reportthree cases of mental retardation in two different families where the mutation in ARX gene c.428_451 dup24 was found while X-fragile syndrome screening was made. Personal and familiar history, phenotype and evolution are described. Conclusion. The molecular analysis of this mutation should be considered as a routine for the genetic diagnosis of mental retardation inmales of nondrafted cause