Speciality
Spotlight

 




 


Obstetric & Gynaecology


 

 




Genetics 

   

  • Triploidy : Antenatal Sonographic Features with Post-mortem correlation

    Mittal TK, Vujanic GM, Morrissey BM, et al (Univ. Hosp. Of Wales, Cardiff)

    Prenat Diagn 18:1253-1262, 1998

          


    Recently, the largest series of triploidy to date was reported, describing the antenatal US scan features in great detail. However postmortem findings were not included. The current study compared antenatal US scan features with postmortem findings to facilitate the sonographic diagnosis and define its limitations.

        


    Conclusion : Triploidy should be considered in all pregnancies with early second-trimester IUGR with or without
    oligohydramnios, a major CNS abnormality, or enlarged placenta with or without changes in partial hydatidiform mole. Because triploidy is associated with increased obstetric complications, clinicians should offer fetal karyotyping to confirm the diagnosis so that appropriate treatment can be initiated.

        


    Triploidy, defined as a genome consisting of 3
    haplotypes, is estimated to occur in 1% of pregnancies, most of which are lost in the form of spontaneous abortions. Karyotypes from spontaneous abortion material show that about 25% represent triploid
    concepti, and the incidence by the second trimester is reduced to .02%.

        


    The most common fetal defects-ventriculomegaly,
    syndactyly, atrioventricular conduction, growth retardation, and
    micrognathia, are not often obvious. In summary, triploidy should be suspected in all cases of partial mole when the placenta contains several areas of focal sonolucency representing vesicles or when severe IUGR occurs in the second trimester.

        

  • CC Kocun, JT Harrigan, et al (Neptune and New Brunswick, New Jersey)

    Changing trends in patient decisions concerning genetic amniocentesis

    Am J Obstet Gynecol 2000; 182: 1018-20)



    Objective : This study was undertaken to determine whether there was a change in patient decisions concerning genetic amniocentesis during the period 1995-1998




    Study Design
    : All patients referred for genetic counseling because of advanced maternal age, abnormal serum triple-screen results, or ultrasonographic abnormalities between January and March 1995 and between January and March 1998 were evaluated through a retrospective chart review. Patient characteristics included age, race and gestational age. Group 1 consisted of patients from 1995. Group 2 consisted of patients from 1998. Data on patient decisions concerning amniocentesis before and after genetic counseling and ultrasonographic examination were compared in each group. Groups 1 and 2 were then comparedd with respect to decisions before and after genetic counseling and ultrasonographic evaluation.



    Results : A total of 112 patients were studied. Group1 consisted of 53 patients and group 2 consisted of 59 patients. When the groups were compared, no differences in age, race, or gestational age were noted. In group1, before counseling, 18 of 53 patients desired genetic testing, compared with 44 of 53 after counseling (P = .02). In group 2, before counseling, 4 of 59 patients desired genetic testing, compared with 15 of 59 after counseling (P =.01). A significantly greater number of patients in group1 than in group2 desired genetic testing both before counseling (n =18/53 vs n =4/59; P =.01) and after counseling (n = 44/53 vs n=15/59; P=.01)





    Conclusion : Fewer patients at risk for Down syndrome in 1998 than in 1995 desired amniocentesis both before and after genetic counseling and ultrasonographic examination.



    Comment : This is probably the result of introduction of maternal serum markers
    screening.

             

  • J. Levron, A. Aviram-Goldring, et al (The Chaim Sheba Medical Center, Tel-Hashomer, and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel)

    Sperm Chromosome Abnormalities in Men with Severe Male Factor Infertility Who Are Undergoing In Vitro Fertilization with Intracytoplasmic Sperm Injection

    Fertil Steril, September 2001; Vol. 76(3): 479-84

           

    Objective : To investigate the potential paternal contribution to the risk of fetal chromosomal anomalies after intracytoplasmic sperm injection (ICSI).

           

    Design : Spermatozoa isolated from testicular tissue and ejaculated specimens of consenting patients undergoing testicular biopsy and ICSI were analyzed for chromosomes X, and Y, and 18 by FISH.

          

    Setting : Assisted reproductive technology program.

           

    Patient(s) : Consenting patients undergoing testicular biopsy and ICSI, severe oligozoospermic patients, and normal fertile donors.

            

    Intervention(s) : None

           

    Main Outcome Measure(s) : The rate of chromosome abnormalities in testicular sperm with regard to the type of azoospermia and ejaculated sperm compared to healthy men.

           

    Result(s) : The mean serum levels of FSH in the groups with nonobstructive azoospermia (n=9), obstructive azoospermia (n=10), severe oligozoospermia (n=9), and the normal donors (n=6) were 17.5 ± 8.2 (P< .05), 3.5 ± 2.6, 14.6 ± 3.5 (P< .05), and 3.1 ± 0.4 IU/mL, respectively.

           

    The corresponding rates of sperm chromosome abnormalities among these groups were 19.6% (P< .001), 8.2% (P< .001), 13.0% (P< .001), and 1.6%, respectively. The corresponding rates of disomy among these groups were 7.8% (12 of 153 spermatozoa), 4.9% (18 of 367), 6.2% (109 of 1,751), and 1% (5 of 500 spermatozoa), respectively. Errors in chromosomes X and Y were significantly more common than in chromosome 18.

           

    Conclusion(s) : The present findings demonstrate a linkage between gonadal failure (high serum FSH levels) and the occurrence of sperm chromosome aneuploidies. The findings may explain the increased incidence of sex chromosome abnormalities found after IVF in the severe male factor patient population. 

          

    Genetic screening during pregnancy or before embryo replacement should be considered carefully.

            

  • Karen
    L Koscica, Joseph C Canterino, et al (Neptune and
    New Brunswick, NJ)

    Assessing genetic risk: Comparison between the
    referring obstetrician and genetic counselor


    Am J Obstet Gynecol, Nov.2001, vol.185:1032-4

      

    Objective: To compare the genetic risk
    assessment of the referring obstetrician to the risk
    assessment of the genetic counselor.

      

    Study Design: All patients evaluated between
    January 1, 1999, and March 31, 1999, and who
    required genetic counseling were retrospectively
    reviewed. The genetic risk assessment of the
    referring obstetrician was compared to the genetic
    risk assessment following counseling by a genetic
    counselor who used a questionnaire and a
    three-generation pedigree. The number of patients
    with additional genetic risk factors identified by
    the genetic counselor were recorded and compared by
    using the McNemar chi-square test. Group
    demographics and characteristics were evaluated.

       

    Results: Among the 145 patients evaluated,
    38% (n=55) had additional genetic risk factors
    detected by the genetic counselor (P=.01). The
    maternal demographics and characteristics did not
    differ between the two groups.

      

    Conclusion: The practice of referring
    high-risk obstetric patients for genetic counseling
    improves the detection of identifiable genetic risk
    factors.

        

      



 

 

Speciality Spotlight

 

 

Genetics 
   

  • Triploidy : Antenatal Sonographic Features with Post-mortem correlation
    Mittal TK, Vujanic GM, Morrissey BM, et al (Univ. Hosp. Of Wales, Cardiff)
    Prenat Diagn 18:1253-1262, 1998
          
    Recently, the largest series of triploidy to date was reported, describing the antenatal US scan features in great detail. However postmortem findings were not included. The current study compared antenatal US scan features with postmortem findings to facilitate the sonographic diagnosis and define its limitations.
        
    Conclusion : Triploidy should be considered in all pregnancies with early second-trimester IUGR with or without oligohydramnios, a major CNS abnormality, or enlarged placenta with or without changes in partial hydatidiform mole. Because triploidy is associated with increased obstetric complications, clinicians should offer fetal karyotyping to confirm the diagnosis so that appropriate treatment can be initiated.
        
    Triploidy, defined as a genome consisting of 3 haplotypes, is estimated to occur in 1% of pregnancies, most of which are lost in the form of spontaneous abortions. Karyotypes from spontaneous abortion material show that about 25% represent triploid concepti, and the incidence by the second trimester is reduced to .02%.
        
    The most common fetal defects-ventriculomegaly, syndactyly, atrioventricular conduction, growth retardation, and micrognathia, are not often obvious. In summary, triploidy should be suspected in all cases of partial mole when the placenta contains several areas of focal sonolucency representing vesicles or when severe IUGR occurs in the second trimester.
        

  • CC Kocun, JT Harrigan, et al (Neptune and New Brunswick, New Jersey)
    Changing trends in patient decisions concerning genetic amniocentesis
    Am J Obstet Gynecol 2000; 182: 1018-20)

    Objective : This study was undertaken to determine whether there was a change in patient decisions concerning genetic amniocentesis during the period 1995-1998

    Study Design : All patients referred for genetic counseling because of advanced maternal age, abnormal serum triple-screen results, or ultrasonographic abnormalities between January and March 1995 and between January and March 1998 were evaluated through a retrospective chart review. Patient characteristics included age, race and gestational age. Group 1 consisted of patients from 1995. Group 2 consisted of patients from 1998. Data on patient decisions concerning amniocentesis before and after genetic counseling and ultrasonographic examination were compared in each group. Groups 1 and 2 were then comparedd with respect to decisions before and after genetic counseling and ultrasonographic evaluation.

    Results : A total of 112 patients were studied. Group1 consisted of 53 patients and group 2 consisted of 59 patients. When the groups were compared, no differences in age, race, or gestational age were noted. In group1, before counseling, 18 of 53 patients desired genetic testing, compared with 44 of 53 after counseling (P = .02). In group 2, before counseling, 4 of 59 patients desired genetic testing, compared with 15 of 59 after counseling (P =.01). A significantly greater number of patients in group1 than in group2 desired genetic testing both before counseling (n =18/53 vs n =4/59; P =.01) and after counseling (n = 44/53 vs n=15/59; P=.01)


    Conclusion : Fewer patients at risk for Down syndrome in 1998 than in 1995 desired amniocentesis both before and after genetic counseling and ultrasonographic examination.

    Comment : This is probably the result of introduction of maternal serum markers screening.
             

  • J. Levron, A. Aviram-Goldring, et al (The Chaim Sheba Medical Center, Tel-Hashomer, and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel)
    Sperm Chromosome Abnormalities in Men with Severe Male Factor Infertility Who Are Undergoing In Vitro Fertilization with Intracytoplasmic Sperm Injection
    Fertil Steril, September 2001; Vol. 76(3): 479-84
           
    Objective : To investigate the potential paternal contribution to the risk of fetal chromosomal anomalies after intracytoplasmic sperm injection (ICSI).
           
    Design : Spermatozoa isolated from testicular tissue and ejaculated specimens of consenting patients undergoing testicular biopsy and ICSI were analyzed for chromosomes X, and Y, and 18 by FISH.
          
    Setting : Assisted reproductive technology program.
           
    Patient(s) : Consenting patients undergoing testicular biopsy and ICSI, severe oligozoospermic patients, and normal fertile donors.
            
    Intervention(s) : None
           
    Main Outcome Measure(s) : The rate of chromosome abnormalities in testicular sperm with regard to the type of azoospermia and ejaculated sperm compared to healthy men.
           
    Result(s) : The mean serum levels of FSH in the groups with nonobstructive azoospermia (n=9), obstructive azoospermia (n=10), severe oligozoospermia (n=9), and the normal donors (n=6) were 17.5 ± 8.2 (P< .05), 3.5 ± 2.6, 14.6 ± 3.5 (P< .05), and 3.1 ± 0.4 IU/mL, respectively.
           
    The corresponding rates of sperm chromosome abnormalities among these groups were 19.6% (P< .001), 8.2% (P< .001), 13.0% (P< .001), and 1.6%, respectively. The corresponding rates of disomy among these groups were 7.8% (12 of 153 spermatozoa), 4.9% (18 of 367), 6.2% (109 of 1,751), and 1% (5 of 500 spermatozoa), respectively. Errors in chromosomes X and Y were significantly more common than in chromosome 18.
           
    Conclusion(s) : The present findings demonstrate a linkage between gonadal failure (high serum FSH levels) and the occurrence of sperm chromosome aneuploidies. The findings may explain the increased incidence of sex chromosome abnormalities found after IVF in the severe male factor patient population. 
          
    Genetic screening during pregnancy or before embryo replacement should be considered carefully.
            

  • Karen L Koscica, Joseph C Canterino, et al (Neptune and New Brunswick, NJ)
    Assessing genetic risk: Comparison between the referring obstetrician and genetic counselor
    Am J Obstet Gynecol, Nov.2001, vol.185:1032-4
      
    Objective: To compare the genetic risk assessment of the referring obstetrician to the risk assessment of the genetic counselor.
      
    Study Design: All patients evaluated between January 1, 1999, and March 31, 1999, and who required genetic counseling were retrospectively reviewed. The genetic risk assessment of the referring obstetrician was compared to the genetic risk assessment following counseling by a genetic counselor who used a questionnaire and a three-generation pedigree. The number of patients with additional genetic risk factors identified by the genetic counselor were recorded and compared by using the McNemar chi-square test. Group demographics and characteristics were evaluated.
       
    Results: Among the 145 patients evaluated, 38% (n=55) had additional genetic risk factors detected by the genetic counselor (P=.01). The maternal demographics and characteristics did not differ between the two groups.
      
    Conclusion: The practice of referring high-risk obstetric patients for genetic counseling improves the detection of identifiable genetic risk factors.
        

      

 

By |2022-07-20T16:43:08+00:00July 20, 2022|Uncategorized|Comments Off on Genetics

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