Somatic cytogenetic and azoospermia factor gene microdeletion studies in infertile men.

The objective of the present study was to determine the frequency of somatic chromosomal anomalies and Y chromosomal microdeletions (azoospermia factor genes, AZF) in infertile males who seek assisted reproduction. These studies are very important because the assisted reproduction techniques (mainly intracytoplasmic sperm injection) bypass the natural selection process and some classical chromosomal abnormalities, microdeletions of AZF genes or some deleterious genic mutations could pass through generations. These genetic abnormalities can cause in the offspring of these patients male infertility, ambiguous external genitalia, mental retardation, and other birth defects. We studied 165 infertile men whose infertility was attributable to testicular problems (60 were azoospermic, 100 were oligospermic and 5 were asthenospermic). We studied 100 metaphases per patient with GTG banding obtained from temporary lymphocyte culture for chromosomal abnormality detection and performed a genomic DNA analysis using 28 Y chromosome-specific sequence-tagged sites for Y AZF microdeletion detection. Karyotyping revealed somatic anomalies in 16 subjects (16/165 = 9.6%). Of these 16, 12 were in the azoospermic group (12/60 = 20%) and 4 were in the oligospermic group (4/100 = 4%). The most common chromosomal anomaly was Klinefelter syndrome (10/165 = 6%). Microdeletions of AZF genes were detected in 12 subjects (12/160 = 7.5%). The frequencies detected are similar to those described previously. These results show the importance of genetic evaluation of infertile males prior to assisted reproduction. Such evaluation can lead to genetic counseling and, consequently, to primary and secondary prevention of mental retardation and birth defects.

Somatic cytogenetic and azoospermia factor gene microdeletion studies in infertile men

The objective of the present study was to determine the frequency of somatic chromosomal anomalies and Y chromosomal microdeletions (azoospermia factor genes, AZF) in infertile males who seek assisted reproduction. These studies are very important because the assisted reproduction techniques (mainly intracytoplasmic sperm injection) bypass the natural selection process and some classical chromosomal abnormalities, microdeletions of AZF genes or some deleterious genic mutations could pass through generations. These genetic abnormalities can cause in the offspring of these patients male infertility, ambiguous external genitalia, mental retardation, and other birth defects. We studied 165 infertile men whose infertility was attributable to testicular problems (60 were azoospermic, 100 were oligospermic and 5 were asthenospermic). We studied 100 metaphases per patient with GTG banding obtained from temporary lymphocyte culture for chromosomal abnormality detection and performed a genomic DNA analysis using 28 Y chromosome-specific sequence-tagged sites for Y AZF microdeletion detection. Karyotyping revealed somatic anomalies in 16 subjects (16/165 = 9.6 percent). Of these 16, 12 were in the azoospermic group (12/60 = 20 percent) and 4 were in the oligospermic group (4/100 = 4 percent). The most common chromosomal anomaly was Klinefelter syndrome (10/165 = 6 percent). Microdeletions of AZF genes were detected in 12 subjects (12/160 = 7.5 percent). The frequencies detected are similar to those described previously. These results show the importance of genetic evaluation of infertile males prior to assisted reproduction. Such evaluation can lead to genetic counseling and, consequently, to primary and secondary prevention of mental retardation and birth defects.

De novo complex chromosome rearrangement: a study of two patients.

Complex chromosome rearrangements (CCR) involving multiple breaks in two or more chromosomes are rare. We describe a girl with development delay and overgrowth who presents a nine-break apparently balanced de novo rearrangement involving chromosomes 1, 2, 3, 4 and 12, and a boy with developmental delay and seizures with a complex three-chromosome apparently balanced de novo rearrangement involving chromosomes 2, 7 and 13. The relationship between clinical abnormalities and apparently balanced rearrangements is discussed.

Effect of paternal age on human sperm chromosomes.

OBJECTIVE: To investigate whether increased age alters the frequency and type of chromosomal anomalies in human spermatozoa. DESIGN: Semen specimens were collected from donors via masturbation; cytogenetic studies were performed on sperm chromosomes after heterologous (human-hamster) in vitro fertilization. SETTING: Cytogenetics Laboratory, Genetics Department, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil. PATIENT(S): Seven men ages 59-74 (older group) and five men ages 23-39 (control group). MAIN OUTCOME MEASURE(S): Frequency and types of chromosomal anomalies in older and control group donors. RESULT(S): The frequency of numerical and structural aberrations (acentric fragments and complex radial figures) was significantly greater in chromosomes of older donors when compared with those of the control group. CONCLUSION(S): The higher frequency of sperm chromosome aberrations in older men was mainly a result of increased nondisjunction, acentric fragments, and complex radial figures.

A viable fetus presenting 68, XX[73]/69, XXX[27] triploid mosaicism

A triploidia é uma anomalia cromossômica comum encontrada em 1 a 2 por cento das gestaçöes clinicamente reconhecidas e em cerca de 15 a 20 por cento dos abortos espontâneos de causa cromossômica. Em aproximadamente 5 por cento dos casos, uma aneuploidia pode estar também associada (Boué et al., 1985). Descrevemos um recém-nascido do sexo feminino, prematuro (30 semanas de idade gestacional), com microcefalia, dismorfias faciais e alteraçöes de membros, que foi a óbito com 1 dia de vida por insuficiência respiratória. O exame anátomo-patológico da placenta revelou alteraçöes compatíveis com degeneraçäo molar. A necrópsia da criança näo evidenciou malformaçöes internas. A análise citogenética de 100 metástases, obtidas a partir de cultura de tecido renal, evidenciou cariótipo 68,XX[73]/69,XXX[27]. Apenas 9 casos de triploidia 68,XX foram descritos anteriormente, sendo 7 em abortos, 1 em feto de 21 semanas e 1 em recém-nascido a termo. Consideramos que este estudo seja o primeiro da literatura relatando a ocorrência de mosaicismo 69,XXX/68,XX em um recém-nascido vivo. Os autores discutem os achados clínicos e os possíveis mecanismos envolvidos nesta aberraçäo cromossômica.

Trisomy 13 mosaicism demonstrated only in skin fibroblasts in a patient presenting psychomotor retardation, pigmentary dysplasia and some dysmorphic features

Os autores descrevem uma criança do sexo feminino com atraso do desenvolvimento neuropsicomotor, manchas hipercrômicas na pele e algumas características dismórficas. O cariótipo em linfócitos de sangue periférico foi normal e a cultura de fibroblastos a partir de biópsia de pele revelou trissomia do cromossomo 13 em 50 por cento das metáfases analisadas. Enfatizam a importância do cariótipo de pele nas situaçöes clínicas em que o retardo psicomotor ou mental está associado com displasia pigmentar de pele e cromossomos normais nos linfócitos.