Molecular characterization of a large cohort of mucopolysaccharidosis patients: Iran Mucopolysaccharidosis RE-diagnosis study (IMPRESsion).

Mucopolysaccharidoses (MPSs) are rare, heterogeneous inborn errors of metabolism (IEM) diagnosed through a combination of clinical, biochemical, and genetic investigations. The aim of this study was molecular characterization of the largest cohort of Iranian MPS patients (302 patients from 289 unrelated families), along with tracking their ethnicity and geographical origins. 185/289 patients were studied using an IEM-targeted NGS panel followed by complementary Sanger sequencing, which led to the diagnosis of 154 MPS patients and 5 non-MPS IEMs (diagnostic yield: 85.9%). Furthermore, 106/289 patients who were referred with positive findings went through reanalysis and confirmatory tests which confirmed MPS diagnosis in 104. Among the total of 258 MPS patients, 225 were homozygous, 90 harbored novel variants, and 9 had copy number variations. MPS IV was the most common type (34.8%) followed by MPS I (22.7%) and MPS VI (22.5%). Geographical origin analysis unveiled a pattern of distribution for frequent variants in ARSB (c.430G>A, c.962T>C [p.Leu321Pro], c.281C>A [p.Ser94*]), GALNS (c.319G>A [p.Ala107Thr], c.860C>T [p.Ser287Leu], c.1042A>G [p.Thr348Ala]), and IDUA (c.1A>C [p.Met1Leu], c.1598C>G [p.Pro533Arg], c.1562_1563insC [p.Gly522Argfs*50]). Our extensive patient cohort reveals the genetic and geographic landscape of MPS in Iran, which provides insight into genetic epidemiology of MPS and can facilitate a more cost-effective, time-efficient diagnostic approach based on the region-specific variants.

International clinical guidelines for the management of phosphomannomutase 2-congenital disorders of glycosylation: Diagnosis, treatment and follow up.

Phosphomannomutase 2 (PMM2-CDG) is the most common congenital disorder of N-glycosylation and is caused by a deficient PMM2 activity. The clinical presentation and the onset of PMM2-CDG vary among affected individuals ranging from a severe antenatal presentation with multisystem involvement to mild adulthood presentation limited to minor neurological involvement. Management of affected patients requires a multidisciplinary approach. In this article, a systematic review of the literature on PMM2-CDG was conducted by a group of international experts in different aspects of CDG. Our managment guidelines were initiated based on the available evidence-based data and experts' opinions. This guideline mainly addresses the clinical evaluation of each system/organ involved in PMM2-CDG, and the recommended management approach. It is the first systematic review of current practices in PMM2-CDG and the first guidelines aiming at establishing a practical approach to the recognition, diagnosis and management of PMM2-CDG patients.

An Iranian Congenital Adrenal Hypoplasia Patient with Elevated Testosterone in Infancy due to a Novel Pathogenic Frameshift Variant in NR0B1.

X-linked congenital adrenal hypoplasia due to NR0B1 mutation is characterized by hypogonadotropic hypogonadism (HH) and infertility. Here, we describe a novel pathogenic frameshift variant in NR0B1 associated with congenital adrenal hypoplasia by whole exome sequencing in an Iranian case with high level of testosterone. Clinical evaluations and pedigree drawing were performed. Point mutations, gene conversions, and large deletions of the CYP21A2 gene were checked. WES and segregation analyses were conducted. In silico analysis was also performed for the novel variant. The ACTH, 17-hydroxy progesterone c, and DHEA sulfate values were elevated up to 624.6 pg/mL, 8.6 pmol/L, and 17.8UMOL/L, respectively. No mutation was found in the CYP21A2 gene. WES identified a novel hemizygous frameshift insertion c.218_219insACCA: p.His73GlnfsTer41 variant in the NR0B1 gene with a pathogenic effect according to ACMG criteria. Genetic testing is helpful for differential diagnosis in primary adrenal insufficiency disorders. NR0B1 may be a common cause of congenital adrenal hypoplasia in our population.