A recurrent homozygous missense DPM3 variant leads to muscle and brain disease.

Biallelic pathogenic variants in the genes encoding the dolichol-phosphate mannose synthase subunits (DPM) which produce mannosyl donors for glycosylphosphatidylinositols, N-glycan and protein O- and C-mannosylation, are rare causes of congenital disorders of glycosylation. Pathogenic variants in DPM1 and DPM2 are associated with muscle-eye-brain (MEB) disease, whereas DPM3 variants have mostly been reported in patients with isolated muscle disease-dystroglycanopathy. Thus far, only one affected individual with compound heterozygous DPM3 variants presenting with myopathy, mild intellectual disability, seizures, and nonspecific white matter abnormalities (WMA) around the lateral ventricles has been described. Here we present five affected individuals from four unrelated families with global developmental delay/intellectual disability ranging from mild to severe, microcephaly, seizures, WMA, muscle weakness and variable cardiomyopathy. Exome sequencing of the probands revealed an ultra-rare homozygous pathogenic missense DPM3 variant NM_018973.4:c.221A>G, p.(Tyr74Cys) which segregated with the phenotype in all families. Haplotype analysis indicated that the variant arose independently in three families. Functional analysis did not reveal any alteration in the N-glycosylation pathway caused by the variant; however, this does not exclude its pathogenicity in the function of the DPM complex and related cellular pathways. This report provides supporting evidence that, besides DPM1 and DPM2, defects in DPM3 can also lead to a muscle and brain phenotype.

Genetic variant profiling of neonatal diabetes mellitus in Iranian patients: Unveiling 58 distinct variants in 14 genes.

INTRODUCTION: Neonatal diabetes mellitus (NDM) is a rare non-immunological monogenic disorder characterized by hyperglycemic conditions primarily occurring within the first 6 months of life. The majority of cases are attributed to pathogenic variants in genes affecting beta-cell survival, insulin regulation, and secretion. This study aims to investigate the genetic landscape of NDM in Iran. METHODS: We recruited a total of 135 patients who were initially diagnosed with diabetes at <12 months of age in Iran and referred to pediatric endocrinology clinics across the country. These patients underwent genetic diagnostic tests conducted by the Exeter Molecular Genetics Laboratory in the UK. The pathogenic variants identified were sorted and described based on type, pathogenicity (according to ACMG/AMP criteria), novelty, and the affected protein domain. RESULTS: Genetic defects were identified in 93 probands, presenting various pathogenic abnormalities associated with NDM and its associated syndromes. 76% of the patients were born as a result of consanguineous marriage, and a familial history of diabetes was found in 43% of the cases. A total of 58 distinct variants in 14 different genes were discovered, including 20 variants reported for the first time. Causative variants were most frequently identified in EIF2AK3, KCNJ11, and ABCC8, respectively. Notably, EIF2AK3 and ABCC8 exhibited the highest number of novel variants. DISCUSSION: These findings provide valuable insights into the genetic landscape of NDM in the Iranian population and contribute to the knowledge of novel pathogenic variants within known causative genes.

5-Alpha reductase deficiency; an important cause of 46, XY DSD: Report of three cases within a family.

Key clinical message: 5-Alpha reductase deficiency is an important cause of 46, XY disorder of sex development. Timely diagnosis and proper management by a multidisciplinary team can lead to a favorable outcome. Sex assignment should be deferred until puberty because spontaneous virilization occurs and the patient can engage in the decision-making process. Abstract: 5-Alpha reductase deficiency is a genetic disorder causing 46, XY disorder of sex development (DSD). Typical clinical feature is a male with ambiguous genitalia or undervirilization at birth. Here we report three cases of this disorder within a family.

Response to sapropterin hydrochloride (Kuvan®) in children with phenylketonuria (PKU): a clinical trial.

Background Phenylketonuria (PKU) is one of the most common types of inborn error of metabolism. The mainstay of therapy for PKU has been dietary phenylalanine (Phe) restriction. Sapropterin dihydrochloride has been shown to be effective in reducing Phe levels in PKU patients. Methods This study was a clinical trial performed in the pediatric endocrine clinic of Imam Reza Hospital, Mashhad, Iran. Results All children between 1 and 10 years of age with a diagnosis of PKU whose serum Phe levels were between 120 and 360 µmol/L, in Khorasan Razavi province in the north-east of Iran, were enrolled. Twenty-four patients were enrolled in the study. Intervention: A free diet for 72 h was allowed and then a 20-mg/kg/day dose of Kuvan® was administered. More than 30% reduction in blood Phe levels was described as responsive. Eight patients responded to the loading test and were eligible for the second stage of the study. In this stage, Phe powder in combination with Kuvan was provided. Patients' serum Phe was measured weekly for 3 months. All eight patients showed Phe tolerance in 3 months, and their serum Phe levels remained within the range. Conclusions Treatment with Kuvan can help reduce blood Phe levels in our pediatric PKU population and allows patients to follow a more liberal diet.

Novel DNA variation of GPR54 gene in familial central precocious puberty.

BACKGROUND: Puberty can be considered the end point of a maturation process which is defined by the dynamic interactions of genes and environmental factors during prenatal and postnatal development. Kisspeptin/G protein-coupled receptor-54, is as an essential gatekeeper and regulator of GnRH neurons, and a key factor in initiation of puberty. Loss and gain of functional mutations in the GPR54 gene are associated with hypogonadotropic hypogonadism and precocious puberty, respectively. This study was designed to evaluate variations of GPR54 in familial precocious puberty. METHODS: Genomic DNA was extracted from peripheral whole blood of 25 subjects with familial precocious puberty. Coding exons 1-5 of the GPR54 gene were amplified by polymerase chain reaction (PCR) and the PCR products were purified and sequenced. DNA sequences were compared to the human GenBank GPR54 sequence using Sequencher sequence alignment software. RESULTS: We detected three different Single Nucleotide Polymorphisms (SNPs) in GPR54: rs10407968 (24A > T) in 13 subjects (52%); rs3050132 (1091 T > A) in 16 subjects (64%), and a novel polymorphism (492C > G) in one subject (4%), while three subjects (12%) had no SNPs. No mutations were found in the GPR54 gene. CONCLUSIONS: Regarding the presence of SNPs in 88% of the subjects in this study, it is likely a relationship exists between the SNPs of the GPR54 gene and familial precocious puberty. Further research is needed to investigate this possibility, and potential functional effects of these polymorphisms.

The Report of Three Rare Cases of the Niemann-pick Disease in Birjand, South Khorasan, Eastern Iran.

Niemann-Pick disease type C (NP-C) is a rare neurovisceral and irreversible disease leading to premature death and disabling neurological signs. This autosomal recessive disease with incidence rate of 1:120000 is caused by mutations in either the NPC1 or the NPC2 gene, which leads to accumulation of cholesterol in body tissues especially brain and progressive neurological symptoms. NP-C is characterized by nonspecific visceral, neurological and psychiatric manifestations in infants. The neurological involvement is typically proceeded by systemic signs (cholestatic jaundice in the neonatal period or isolated spleno-or hepatosplenomegaly in infancy or childhood). Early detection of NPC is important so that therapy with miglustat can delay onset of neurological symptoms and prolong survival. We describe here three infants from Birjand, South Khorasan, eastern Iran in 2016 with splenomegaly and different neurological signs that diagnosis was confirmed by genetic study. In all of them, NPC-509 was pathologically increased. They also had an unreported homozygous mutation (c.1415T>C, p.Leu472Pro) in exon 9 of the NPC1 gene. We found unreported homozygous mutation in NPC gene. Knowing this mutation is significant to our people. Genotype-phenotype correlations for this specific mutation needs to be further studied.