Browsing by Author "Urban, M. F."

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    Cancer genetics : an approach to suspected hereditary breast or colorectal cancer
    (Health & Medical Publishing Group, 2019) Scott, C. J.; Schoeman, M.; Urban, M. F.
    ENGLISH ABSTRACT: Two of the most common cancers are breast cancer and colorectal cancer. Up to 10% of cases of each are associated with a high risk of recurrence in an affected individual, or of occurrence in biological relatives. This results from the presence of an underlying mutation (or ‘pathogenic variant’) in a high-penetrance gene. Such cases are typically associated with an autosomal dominant pattern of inheritance, although this may not be obvious in the family history. Genetic testing can identify many (but not all) of these cases, and should be offered to those whose family history or clinical features suggest a high risk. Although testing for certain risk genes (e.g. BRCA1 or BRCA2) has been available for years, the advent of next-generation sequencing ‘gene panels’ now allows for simultaneous testing of many more genes at lower cost. This allows for more frequent detection of pathogenic variants in underlying genes than in the past, but also makes interpretation more complex. An index of suspicion for genetic cancers and appropriate referral to a genetics health professional are increasingly important.
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    Effectiveness of prenatal screening for Down syndrome on the basis of maternal age in Cape Town
    (Health and Medical Publishing Group (HMPG), 2011) Urban, M. F.; Stewart, C.; Ruppelt, T.; Geerts, L.
    Objective. The prenatal screening programme for Down syndrome (DS) in the South African public health sector remains primarily based on advanced maternal age (AMA). We assessed the changes over time and effectiveness of this screening programme within a Cape Town health district. Methods. Retrospective analysis of the Groote Schuur Hospital Cytogenetic Laboratory and Pregnancy Counselling Clinic databases and audit of maternal delivery records at a primary health care facility. Results. The number of amniocenteses performed for AMA in consecutive 5-year periods reduced progressively from 786 in 1981 - 1985 to 360 in 2001 - 2005. Comparing prenatal with neonatal diagnoses of DS, the absolute number and the proportion diagnosed prenatally have remained relatively constant over time The Pregnancy Counselling Database showed that, of 507 women receiving genetic counselling for AMA in 2008 - 2009, 158 (31.1%) accepted amniocentesis - uptake has reduced considerably since the early 1990s. The audit of women delivering at a primary care facility found that only 10 (16.4%) of 61 AMA women reached genetic counselling in tertiary care: reasons included late initiation of antenatal care and low referral rates from primary care. Conclusion. Prenatal screening and diagnosis for DS based on AMA is working ineffectively in the Cape Town health district assessed, and this appears to be representative of a broader trend in South Africa. Inclusion of fetal ultrasound in the process of prenatal screening for DS should be explored as a way forward.
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    Neural tube defect diagnosis and outcomes at a tertiary South African hospital with intensive case ascertainment
    (Health & Medical Publishing Group, 2019) Krzesinski, E. I.; Geerts, L.; Urban, M. F.
    Background. Neural tube defects (NTDs) are an important category of birth defect, but surveillance remains inadequate in South Africa. Objectives. To assess the identification of NTDs at a tertiary hospital using a range of prenatal, perinatal and postnatal data sources, and to estimate the impact of prenatal diagnosis and birth prevalence for the referral area. Methods. Cases of anencephaly, encephalocele and spina bifida (SB) in a 6-year period were retrospectively identified from 5 data sources covering prenatal, perinatal and postnatal care. These were cross-correlated to avoid duplicate entries and to determine the contribution of different data sources. Details of prenatal diagnosis and termination of pregnancy (TOP) were obtained for 10 years, and birth prevalence over 2 years. Results. During a 6-year period 195 NTDs were identified at a Western Cape Province tertiary hospital. These included 59 (30%) cases of anencephaly, 28 (14%) of encephalocele and 108 (55%) of SB. The majority of NTDs (71%) were detected prenatally, although SB was less commonly diagnosed prenatally than cranial defects (56% v. 88%; p<0.001). Of SB cases ascertained pre- or postnatally, 57% of patients were born alive and 50% discharged alive, but 72% of survivors had not been diagnosed prenatally. Women receiving prenatal diagnosis of any type of NTD before 24 weeks’ gestation were nearly always offered TOP, and the majority accepted termination after non-directive counselling. For SB, later prenatal diagnosis was associated with much lower termination rates because the option was less often offered (51% v. 100%; p<0.001), and perhaps less often accepted (57% v. 78%; p=0.06). The estimated NTD birth prevalence for the referral area was 0.76 - 0.80 per 1 000 live births, but perhaps up to 1.18 per 1 000 when considering under-referral of lethal cranial lesions from rural areas. Conclusions. A substantial number of NTDs can be ascertained from a tertiary hospital environment if multiple data sources are used, even though adding data from the Perinatal Problem Identification Program for outlying health facilities increases detection of lethal defects. Hospital-based surveillance can be considered, especially for SB. Prenatal diagnosis was fairly common and pregnancy termination was often offered and accepted if detected before 24 weeks’ gestation. A regional prenatal ultrasound programme, predominantly based in primary care but with ready access to a tertiary centre, can be quite effective, although limited or delayed access to prenatal diagnosis must be addressed.