First report of a patient with homozygous hemoglobin Ernz: Evidence to support a non-pathogenic variant.

Hemoglobin Ernz (Hb Ernz) is a missense variant in ß-globin caused by a Threonine to Asparagine substitution at the 123rd amino acid position and HBB c.371C > A in gene level. Hb Ernz has been classified as Uncertain Significance (VUS) by ACMG due to limited reports and the absence of any homozygote genotypes. In our study, we found eight cases of Hb Ernz by DNA sequencing of the ß-globin gene during >20 years of Thalassemia Screening in individuals with borderline hematological parameters who were possible carriers of thalassemia or their spouses. We also report the first homozygote variant of Hb Ernz. Our findings suggest that the changes in hematological parameters observed in individuals with Hb Ernz are likely due to α-globin gene mutations rather than Hb Ernz itself. These findings support the reclassification of Hb Ernz as a benign variant in variant classification.

Mutational Analysis and Genotype Investigation of Less Known Gaucher Mutations through Haplotype Analysis in Iranian Gaucher Patients.

Gaucher's disease (GD) is the most frequent lysosomal storage disorder resulting from a deficiency of the enzyme glucocerebrosidase (GBA) which causes the accumulation of glucocerebroside. More than 500 mutations have been reported on the GBA gene so far. In this study, we aimed to investigate more on the genotype of less known mutations through haplotype analysis to explain their disease-causing inheritance. Eight patients and three carriers from nine different families were enrolled in the study. DNA sequencing of all GBA gene's exons was performed and pathogenicity of the mutations was investigated. Using GBA gene-linked STR markers, allele segregations were determined in some families. A total of six different mutations were determined. Five and three patients were identified to carry mutations in homozygous and compound heterozygote patterns respectively, three participants also were identified as carriers. The most prevalent mutations were c.1448 T>C and RecNcil, however, three less common mutations were identified (i.e., c.1223 C>T, c.1315 A>G, and c.1214 G>C). In conclusion, we evaluated six different mutations in Iranian patients and elucidated the inheritance of the three less-known mutations by linkage analysis.

Comprehensive Mutation Analysis and Report of 12 Novel Mutations in a Cohort of Patients with Spinal Muscular Atrophy in Iran.

Spinal muscular atrophies (SMAs) are a heterogeneous group of neuromuscular diseases characterized by loss of motor neurons, muscle weakness, hypotonia and muscle atrophy, with different modes of inheritance; however, the survival motor neuron 1 (SMN1) gene is predominantly involved. The aims of the current study were to clarify the genetic basis of SMA and determine the mutation spectrum of SMN1 and other associated genes, in order to provide molecular information for more accurate diagnosis and future prospects for treatment. We performed a comprehensive analysis of 5q SMA in 1765 individuals including 528 patients from 432 unrelated families with at least one child with suspected clinical presentation of SMA. Copy number variations of the SMN1 and SMN2 genes and linkage analysis were performed using multiplex ligation-dependent probe amplification (MLPA) and short tandem repeat (STR) markers linked to the SMN1 gene. Cases without mutation in the SMA locus on 5q were analyzed for the DNAJB2, IGHMBP2, SIGMAR1 and PLEKHG5 genes using linked STR markers. Sanger sequencing of whole genes was performed for cases with homozygous haplotypes. Whole-genome sequencing (WGS) and whole-exome analysis was conducted for some of the remaining cases. Mutations in the SMN1 gene were identified in 287 (66.43%) families including 269 patients (62.26%) with homozygous deletion of the entire SMN1 gene. Only one of the patients had a homozygous point mutation in the SMN1 gene. Among the remaining families, three families showed mutations in either the DNAJB2, SIGMAR1 or PLEKHG5 genes, which were linked using STR analysis and Sanger sequencing. From 10 families who underwent WGS, we found six homozygous point mutations in six families for either the TNNT1, TPM3, TTN, SACS or COL6A2 genes. Two mutations in the PLA2G6 gene were also found in another patient as compound heterozygous. This rather large cohort allowed us to identify genotype patterns in Iranian 5q SMA patients. The process of identifying 11 mutations (9 novel) in 9 different genes among non-5q SMA patients shows the diversity of genes involved in non-5q SMA in Iranians. Genotyping of patients with SMA is essential for prenatal and preimplantation genetic diagnosis (PGD), and may be very helpful for guiding treatment, with the advent of new, more effective, albeit very expensive, therapies. Also, combining linkage analysis was shown to be beneficial in many ways, including sample authenticity and segregation analysis, and for ruling out maternal cell contamination during prenatal diagnosis (PND).