RESUMO
The potential of assisted reproduction techniques to transmit genetic defects causing male infertility raises questions concerning the need for a systematic genetic screen and counselling. Deletions of the long arm of the Y chromosome are frequently associated with a failure of spermatogenesis. The search for Y specific sequences and for the gene families RNA binding motif (RBM) and deleted in azoospermia (DAZ) have been introduced in many laboratories. The incidence of Y microdeletions varies widely between studies, from 1-55%. These differences are mainly related to study design. The highest incidence of microdeletions has been reported in well selected idiopathic azoospermic patients. Since microdeletions have been reported also in non-idiopathic patients, it is important to define what is the deletion frequency in unselected patients. We report Y chromosome microdeletion screening in 134 unselected patients undergoing intracytoplasmic sperm injection (ICSI). In the first part of the study we tested six Y chromosome markers. We found three patients with microdeletions (2.2%). Subdivision of the study population revealed a deletion incidence of 4.7% in azoospermic/cryptozoospermic patients; an incidence of 7% in idiopathic patients and an incidence of 16% in idiopathic azoospermic/cryptozoospermic patients. The second part of the study consisted of a screen for the presence of the Y chromosome genes, DBY, CDY, XKRY, eIF-1A, DAZ and BPY2. No additional gene-specific deletions were found. Further data on gene specific screening are needed especially for selected idiopathic patients.
Assuntos
Deleção Cromossômica , Fertilização in vitro , Infertilidade Masculina/genética , Infertilidade Masculina/terapia , Cromossomo Y/genética , Sequência de Bases , Aberrações Cromossômicas , Citoplasma , Primers do DNA/genética , Feminino , Frequência do Gene , Testes Genéticos , Humanos , Infertilidade Masculina/etiologia , Masculino , Microinjeções , Oligospermia/genética , Oligospermia/terapia , Reação em Cadeia da Polimerase , Sitios de Sequências Rotuladas , EspermatozoidesRESUMO
The fragile X mutation is the result of an abnormal expansion of a CGG repeat sequence in the FMR-1 gene. Molecular techniques enable the detection of the mutation and also of the exact length of this DNA sequence, allowing the classification of the tested subjects as normal, carrier or affected. We propose a protocol of analysis that combines a method of non-radioactive PCR, Southern blotting and cytogenetic testing. This protocol can be used for screening programme of selected groups of mentally retarded individuals and for prevention studies in families at risk.
Assuntos
Southern Blotting/métodos , Síndrome do Cromossomo X Frágil/diagnóstico , Reação em Cadeia da Polimerase/métodos , Feminino , Síndrome do Cromossomo X Frágil/genética , Humanos , MasculinoRESUMO
The authors present four children, two males and two females, with a 9p duplication, derived from various chromosome rearrangements, diagnosed using clinical, cytogenetic and biochemical evaluations. In particular, GALT dosage allowed them to define with accuracy the different chromosome break-points.