Relevance of genetic counselling in couples prior to intracytoplasmic sperm injection

Abstract

Since the first reports of successful pregnancies after treatment with intracytoplasmic sperm injection (ICSI) in humans numerous attempts have been made to assess the genetic risks of this highly invasive technique. During the study period (February 1995-November 96), 142 couples were referred to our genetic counselling unit prior to ICSI. In three couples, genetic counselling revealed a high recurrence risk for a monogenic disease (myotonic dystrophy, hereditary ataxia and polycystic kidney disease). In nine out of 128 men (7%) an abnormal karyotype was identified, including three Robertsonian translocations, two reciprocal translocations, three sex chromosome aberrations and one case with centric fission of chromosome no. 7. A total of 14 men refused chromosomal analysis. Only one of the 122 women examined had an abnormal karyotype (47, XXX). Five out of six men with congenital bilateral absence of the vas deferens (CBAVD) had at least one mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Three had mutations in both CFTR alleles, including one case in which the second mutation was the 5T allele. One patient with CBAVD and a single Delta F508 CFTR mutation also had left renal agenesis. In conclusion, we strongly recommend that genetic counselling, chromosomal analysis and, in the case of CBAVD, screening for CFTR mutations should be offered to all couples with a diagnosis of male or idiopathic infertility.

Cytogenetic Investigations of Infertile Men With Low Sperm Counts: A 25‐Year Experience

“…Because it is easy to detect these aberrations, an efficient screening of carriers can be offered to all at risk family members who possess a particular proband. Women relatives are likely to be asymptomatic, whereas men may bear the same anomaly without concomitant infertility (Pauer et al, 1997). In children born with unbalanced chromosomal abnormalities, the carrier of the abnormality is in fact, more likely to be the mother than the father (Boue et al, 1984;Daniel and Hook, 1989;Guichaoua et al, 1990;Gardner and Sutherland, 1996).…”

Pure and complete 12p trisomy due to a maternal centric fission of chromosome 12

“…Its frequency may be underestimated because the carriers usually have a normal phenotype. However, they have an increased risk for infertility, spontaneous abortion, stillbirths, and liveborns with congenital malformations [Pauer et al, 1997;Shim et al, 2007]. After the centric fission event, different types of fission products might be observed including telocentric chromosomes, isochromosomes, ring chromosomes, and whole arm translocations for one arm along with an isochromosome for the other [Perry et al, 2004].…”

“…With the exception of chromosomes 1 [Bakshi et al, 2003], 4 [Dallapiccola et al, 1976;Del et al, 1984;Nucaro et al, 1988], 7 [Hansen, 1975;Janke, 1982;Pauer et al, 1997], 9 [Surana et al, 1976], 10 [Fryns et al, 1980], 11 [Shim et al, 2007], 18 [Prabhakar et al, 1994], 21 [Bogart et al, 1995], and X [Therman et al, 1981] there is still very limited information on the mechanism of centric fission in humans. For chromosome 12, there is no report of simple centric fission leading to pure and complete trisomy 12p syndrome.…”

Aspectos Genéticos Do Fator Masculino Na Infertilidade

“…Pacientes com oligozoospermia, apresentam cerca de 3 a 8% de alterações cromossomicas (Prauer et al, 1997). Na oligozoospermia, os desarranjos nos cromossomos autossômicos, representam aproximadamente 2/3 restando 1/3 para os cromossomos sexuais.…”