Deficiency of asparagine synthetase causes congenital microcephaly and a progressive form of encephalopathy.

We analyzed four families that presented with a similar condition characterized by congenital microcephaly, intellectual disability, progressive cerebral atrophy, and intractable seizures. We show that recessive mutations in the ASNS gene are responsible for this syndrome. Two of the identified missense mutations dramatically reduce ASNS protein abundance, suggesting that the mutations cause loss of function. Hypomorphic Asns mutant mice have structural brain abnormalities, including enlarged ventricles and reduced cortical thickness, and show deficits in learning and memory mimicking aspects of the patient phenotype. ASNS encodes asparagine synthetase, which catalyzes the synthesis of asparagine from glutamine and aspartate. The neurological impairment resulting from ASNS deficiency may be explained by asparagine depletion in the brain or by accumulation of aspartate/glutamate leading to enhanced excitability and neuronal damage. Our study thus indicates that asparagine synthesis is essential for the development and function of the brain but not for that of other organs.

Dyssegmental dysplasia, Silverman-Handmaker type: prenatal ultrasound findings and molecular analysis.

OBJECTIVES: The objective of this study is to describe the prenatal sonographic features and the results of DNA analysis on three fetuses with dyssegmental dysplasia, Silverman-Handmaker type (DD-SH). METHODS: A retrospective review of three fetuses with confirmed DD-SH was conducted. The fetal ultrasound findings, the radiological characteristics, and the results of the mutation analysis of the heparan sulphate perlecan gene 2 (HSPG2) were reviewed. RESULTS: There were three cases in two families with DD-SH diagnosed prenatally. The main prenatal ultrasound and the radiological features of DD-SH were severe limb shortening and vertebral segmentation and fusion defects (anisospondyly). The DNA analysis of the HSPG2 gene showed that the two affected fetuses in a nonconsanguineous family had a compound heterozygote for the c.646G > T transversion in exon 7 and a c.5788C > T transition in exon 46. The fetus born to the consanguineous couple had a homozygous mutation c.1356-27_1507 + 59del. CONCLUSION: DD-SH can be diagnosed prenatally using fetal ultrasound as early as 13 weeks. Xrays and DNA analysis of the HSPG2 gene are important for the confirmation of the diagnosis and for the preimplantation and prenatal diagnosis in pregnancies at risk.

The role and impact of personal faith and religion among genetic service providers.

This paper describes the impact of genetic service providers' personal faith and religious values on their experiences interacting with colleagues and patients. We surveyed 480 clinical geneticists (MDs), genetic counselors (GCs), and genetic nurses randomly selected from their professional associations, and then interviewed a sample of survey respondents. Outcomes included religiosity, coping with distress through spiritual beliefs, and personal value conflicts (PVCs). Two hundred fourteen providers completed the survey out of an estimated 348 eligible (61% response rate). Importance attributed to regular attendance at religious services ranged from 39% (not at all important) to 27% (very important). Reliance on religion and spiritual beliefs as a source of comfort ranged from 48% (never) to 33% (sometimes or often). Religiosity varied by discipline with 58% of nurses thinking regular attendance at religious services was moderately or very important as compared to 47% of GCs and 30% of MDs (P = 0.006). Ten percent of respondents had difficulty reconciling their own faith with being a genetics professional, 14% felt the need to hide their own faith from their colleagues or patients, 7% thought their professional stance was not consistent with their personal values, and 4% felt ostracized by the genetics community because of their personal beliefs. The experience of such PVCs was positively correlated with religiosity (r = 0.35; P < 0.0001). GCs were more likely to experience PVCs than MDs or nurses (P = 0.013). Data from the interviews (N = 54) support these findings. A significant minority of genetic service providers are religiously observant and rely on their religious values to cope with distress. These individuals often experience difficulty reconciling their religious beliefs with the expectations of their profession, and sharing their beliefs with their colleagues and patients. Efforts should be made to prevent or reduce the secrecy surrounding personal faith and religion among genetics professionals.