A novel mutation of LAMB2 in a multigenerational mennonite family reveals a new phenotypic variant of Pierson syndrome.

PURPOSE: To describe a novel laminin ß-2 (LAMB2) mutation associated with nephrotic syndrome and severe retinal disease without microcoria in a large, multigenerational family with Pierson syndrome. DESIGN: Retrospective chart review and prospective family examination. PARTICIPANTS: An extended consanguineous family of 52 members. METHODS: The eyes, urine, and serum DNA were evaluated in all family members after discovering 2 patients, both younger than 10 years, with bilateral retinal detachments and concurrent renal dysfunction. Linkage analysis was performed in the 9 living affected individuals, 7 using the Illumina Human Hap370 Duo Bead Array (Illumina, San Diego, CA) and 2 using GeneChip 10K (Affymetrix, Santa Clara, CA) mapping arrays. MAIN OUTCOME MEASURES: The prevalence and severity of ocular and kidney involvement and genetic findings. RESULTS: Eleven affected family members were identified (9 living), all manifesting chronic kidney disease and bilateral chorioretinal pigmentary changes, with or without retinal detachments, but without microcoria or neurodevelopmental deficits, segregating in an autosomal recessive pattern. The causative gene was localized to a 9-Mb region on chromosome 3. Comprehensive gene sequencing revealed a novel LAMB2 variant (c.440A → G; His147R) that was homozygous in the 9 living, affected family members, observed at a frequency of 2.1% in the Old Order Mennonite population, and absent in 91 non-Mennonite controls. The mutation is located in a highly conserved site in the N-terminal domain VI of LAMB2. CONCLUSIONS: This study describes a novel mutation of LAMB2 and further expands the spectrum of eye and renal manifestations associated with defects in the laminin ß-2 chain. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Outcome of chromosomally abnormal pregnancies in Lebanon: obstetricians' roles during and after prenatal diagnosis.

OBJECTIVES: To better understand obstetrician experiences in Lebanon when disclosing abnormal amniocentesis results. METHODS: Structured interviews with 38 obstetricians identified as caregivers from the American University of Beirut Medical Center Cytogenetics Laboratory database of patients with abnormal amniocentesis results between 1999 and 2005. RESULTS: Obstetricians were primarily male, Christian, and with an average of 14 years of experience. They reported doing most pre-amniocentesis counseling, including discussion of risk for common autosomal aneuplodies (95%), and procedure-related risk (95%). Obstetricians reported that 80% of patients at risk for aneuploidy underwent amniocentesis. The study population reported on 143 abnormal test results (124 autosomal abnormalities). When disclosing results, obstetricians reportedly discussed primarily physical and cognitive features of the diagnosis. They varied in levels of directiveness and comfort in providing information. Our records showed that 59% of pregnancies with sex chromosome abnormalities were terminated compared to 90% of those with autosomal aneuploidies; various reasons were proposed by obstetricians. CONCLUSIONS: This study is among the few to assess prenatal diagnosis practices in the Middle East, with a focus on the role of the obstetrician. Given the influence of culture and social norms on prenatal decision-making, it remains important to understand the various impacts on clinical practice in many nations.