Prenatal genetic screening in the Ashkenazi Jewish population

Prenatal healthcare providers' Gaucher disease carrier screening practices

PURPOSE

Gaucher disease carrier screening is controversial in the medical community. The goal of this study was to explore current Gaucher disease carrier screening practices of prenatal healthcare providers.

METHODS

Prenatal healthcare providers were invited by email to complete an electronic-based survey.

RESULTS

A total of 1,454 prenatal healthcare providers, including 209 genetic counselors, 450 midwives, and 795 physicians, completed the study. The majority of genetic counselors (n = 208/209, >99%), physicians (n = 415/450, 92%), and midwives (n = 634/795, 80%) currently offer Jewish ancestry disease carrier screening to couples in whom one or both partners are Jewish. Of providers who offer Jewish ancestry disease screening, the majority of genetic counselors (n = 199/208, 96%) and physicians (n = 352/415, 85%) always or sometimes offer Gaucher disease screening whereas the majority of midwives (n = 357/634, 56%) never offer Gaucher disease screening.

CONCLUSION

This study presents the first report of Gaucher disease carrier screening practices of the prenatal healthcare providers in North America. Our results indicate that Gaucher disease carrier screening is being offered at a high rate within the scope of Jewish ancestry-based carrier screening. This may highlight a need to move away from the debate as to whether Gaucher disease carrier screening should be offered and, instead, focus on how best to provide Gaucher disease carrier screening services.

Can population-based carrier screening be left to the community?

As more genes and mutations are identified in diseases for which particular populations are at increased risk, it is becoming more important to address the social interface between communities and carrier screening. While disproportionately targeted in genetic research, the Orthodox Jewish community often shies away, due to social and religious constraints, from genetic testing and counseling offered by the public health system. The solution is provided by Dor Yeshorim--a program which has become for many a prototype for the successful merging of modern reprogenetic screening and traditional communities. My commentary focuses on the gaps between the rationale and practice of Dor Yeshorim, and the implications of these gaps regarding the trade-off involved in leaving carrier screening to the community. I conclude with a set of questions raised by the implications of the unintended consequences of community genetics.

Type 1 Gaucher disease: null and hypomorphic novel chitotriosidase mutations-implications for diagnosis and therapeutic monitoring

Human plasma chitotriosidase (Chito) is a useful diagnostic and therapeutic biomarker for Type 1 Gaucher disease (GD). However, approximately 40% of Caucasians are heterozygous or homozygous for a common null mutation, c.1049_1072dup24 (dup24) in the chitotriosidase gene (chitinase 1, CHIT1), that complicates interpretation for heterozygotes and precludes use for null homozygotes. 320 Type 1 GD patients were screened for CHIT1 genotype and plasma Chito enzyme levels; 37% were heterozygous and 4% were homozygous for the CHIT1 dup24 allele. Four patients who had no or very low plasma Chito activities had wild-type (wt)/dup24 or wt/wt CHIT1 genotypes, suggesting the presence of other mutations. Sequencing their CHIT1 genes revealed three novel mutations: p.E74K (E74K), p.G102S (G102S), and a complex exon 10 lesion (c.[1060G>A; 1155G>A; 1156+5_1156+8delGTAA], p.[G354R; L385L; missplicing], designated "complex E/I-10"). The G102S mutation was common in Type 1 GD patients and controls ( approximately 30% of alleles). In contrast, the E74K mutation was rare, present only in three Type 1 GD patients ( approximately 1% of alleles), all of Ashkenazi Jewish (AJ) descent, but it was not found in normal controls. The complex E/I-10 mutation occurred in two Caribbean Hispanic/African Type 1 GD patients and was present in 0 to 6% of alleles among normal controls from different populations. In vitro expression demonstrated that the E74K and G102S alleles had approximately 51% and approximately 23% of wild-type Chito catalytic efficiency, respectively. Expression of the G354R allele alone or with the L385L silent substitution did not produce detectable Chito activity or protein. RNA studies indicated that the complex E/I-10 allele also caused missplicing. Recognition of these mutations, particularly G102S, will facilitate the use and interpretation of plasma Chito activities for disease diagnosis, estimating disease severity, and monitoring therapeutic efficacy in GD.

Paediatric rehabilitation in Israel: unique problems, exceptional solutions

Mind the gap: Israel straddles the gap between Western medicine and Middle-Eastern cultural and political challenges. Maintaining state-of-the-art paediatric rehabilitation in an era of economic and political constrictions is described and analysed in this review.

Carrier screening panels for Ashkenazi Jews: is more better?

PURPOSE

To describe the characteristics of Ashkenazi Jewish carrier testing panels offered by US Laboratories, including what diseases are included, the labels used to describe the panels, and the prices of individual tests compared to the prices of panels for each laboratory.

METHODS

GeneTests (http://www.genetests.org) was searched for laboratories that offered Tay-Sachs disease testing. Information was obtained from laboratory web sites, printed brochures, and telephone calls about tests/panels.

RESULTS

Twenty-seven laboratories offered up to 10 tests. The tests included two diseases associated with death in childhood (Niemann-Pick type A and Tay-Sachs disease), five with moderate disability and a variably shortened life span (Bloom syndrome, Canavan disease, cystic fibrosis, familial dysautonomia, Fanconi anemia, and mucolipidosis type IV), and two diseases that are not necessarily disabling or routinely shorten the lifespan (Gaucher disease type I and DFNB1 sensorineural hearing loss). Twenty laboratories offered a total of 27 panels of tests for three to nine diseases, ranging in price from $200 to $2082. Of these, 15 panels cost less than tests ordered individually. The panels were described by 24 different labels; eight included the phrase Ashkenazi Jewish Disease or disorder and six included the phrase Ashkenazi Jewish Carrier.

CONCLUSION

There is considerable variability in the diseases, prices, and labels of panels. Policy guidance for establishing appropriate criteria for inclusion in panels may be useful to the Ashkenazi Jewish community, clinicians, and payers. Pricing strategies that offer financial incentives for the use of "more tests" should be reexamined.