A Novel Homozygous Frameshift Variant in DYM Causing Dyggve-Melchior-Clausen Syndrome in Pakistani Patients.

Background: Dyggve-Melchior-Clausen syndrome (DMC) is a skeletal dysplasia with associated defects of brain development and intelligence. The truncating pathogenic variants in DYM are the most frequent cause of DMC. Smith-McCort (SMC), another skeletal dysplasia, is also caused by non-synonymous DYM variants. Methods and Results: In the current study, we examined a Pakistani consanguineous family with three affected members. Clinical features like spondyloepimetaphyseal dysplasia, indicative of characteristic skeletal abnormalities, and intellectual disability were observed. Our male patients had microcephaly and coarse facial features while the female patient did not represent microcephaly or abnormal facies, which are significant features of DMC patients. Sanger sequencing identified a novel homozygous frameshift insertion (c.95_96insT, p.W33Lfs*14) in DYM, which likely leads to nonsense-mediated decay (NMD). Conclusion: The novel frameshift change verifies the fact that pathogenic variants in DYM are the most frequent cause of DMC.

Exome sequencing and metabolomic analysis of a chronic kidney disease and hearing loss patient family revealed RMND1 mutation induced sphingolipid metabolism defects.

Mitochondrial disorders (MIDs) shows overlapping clinical presentations owing to the genetic and metabolic defects of mitochondria. However, specific relationship between inherited mutations in nuclear encoded mitochondrial proteins and their functional impacts in terms of metabolic defects in patients is not yet well explored. Therefore, using high throughput whole exome sequencing (WES), we screened a chronic kidney disease (CKD) and sensorineural hearing loss (SNHL) patient, and her family members to ascertain the mode of inheritance of the mutation, and healthy population controls to establish its rare frequency. The impact of mutation on biophysical characteristics of the protein was further studied by mapping it in 3D structure. Furthermore, LC-MS tandem mass spectrophotometry based untargeted metabolomic profiling was done to study the fluctuations in plasma metabolites relevant to disease causative mutations and kidney damage. We identified a very rare homozygous c.631G > A (p.Val211Met) pathogenic mutation in RMND1 gene in the proband, which is inherited in an autosomal recessive fashion. This gene is involved in the mitochondrial translational pathways and contribute in mitochondrial energy metabolism. The p.Val211Met mutation is found to disturb the structural orientation (RMSD is -2.95 Å) and stability (ΔΔG is -0.552 Kcal/mol) of the RMND1 protein. Plasma metabolomics analysis revealed the aberrant accumulation of metabolites connected to lipid and amino acid metabolism pathways. Of these metabolites, pathway networking has discovered ceramide, a metabolite of sphingolipids, which plays a role in different signaling cascades including mitochondrial membrane biosynthesis, is highly elevated in this patient. This study suggests that genetic defects in RMND1 gene alters the mitochondrial energy metabolism leading to the accumulation of ceramide, and subsequently promote dysregulated apoptosis and tissue necrosis in kidneys.

A Novel Homozygous Frameshift Mutation in CCN6 Causing Progressive Pseudorheumatoid Dysplasia (PPRD) in a Consanguineous Yemeni Family.

Background: Progressive pseudorheumatoid dysplasia (PPRD) inherited in an autosomal recessive fashion, is a disabling disease, characterized by platyspondyly, irregularities of the vertebral bodies, narrowing of the intervertebral discs and intraarticular spaces, widening of the epiphysis-metaphysis, polyarthralgia, multiple joint contractures, and disproportionate short stature. A number of studies have been performed on this deformity in various populations around the globe, including the Arab population. Mutations in CCN6, located on 6q22, are reported to cause this anomaly. Case Presentation: The present study describes the investigation of a consanguineous family of Yemeni origin. Clinical examination of the patient revealed short stature with progressive skeletal abnormalities, stiffness and enlargement of small joints of the hands along with restriction of movements of proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints with weakness and gait disturbance. Sanger sequencing revealed a novel homozygous frameshift deletion mutation (c.746delT; p.Val249Glyfs*10) in CCN6 which may lead to NMD (Nonsense mediated decay). This mutation expands the spectrum of pathogenic variants in CCN6 causing PPRD.

Erratum: Attitude toward Prenatal Testing and Termination of Pregnancy among Health Professionals and Medical Students in Saudi Arabia.

[This corrects the article DOI: 10.1055/s-0037-1600131.].

Case of Sjögren-Larsson syndrome with a large deletion in the ALDH3A2 gene confirmed by single nucleotide polymorphism array analysis.

Sjögren-Larsson syndrome (SLS) is a neurocutaneous disorder inherited in an autosomal recessive fashion. SLS patients are characterized by lipid metabolism error, primarily leading to cardinal signs of ichthyosis, spasticity and mental retardation. Additional signs include short stature, epilepsy, retinal abnormalities and photophobia. More than 90 mutations of the ALDH3A2 gene have been reported for SLS, and such variants can be successfully detected at a rate of 94% by direct DNA sequencing. We performed direct sequencing of ALDH3A2 gene from the index patient, however, no mutation could be detected. HumanCytoSNPs12 array analysis and subsequent targeted single nucleotide polymorphism analysis revealed a novel deletion mutation at chromosome 17p11.2. This 67-Kb region includes the first five coding exons of ALDH3A2, and is flanked by rs2245639 and rs962801. To the best of our knowledge, this mutation is novel and our findings broaden the mutation spectrum of ALDH3A2 causing SLS phenotype.

Structural chromosomal abnormalities in couples with recurrent abortion in Egypt.

BACKGROUND/AIM: To evaluate the incidence of chromosomal abnormalities in couples who experience recurrent abortion and identify additional factors that may be predictive of abortion, such as parental age and unfavorable obstetric or abnormal semen analysis. MATERIALS AND METHODS: The present study examined 125 couples who had experienced recurrent abortion. All subjects provided a detailed personal medical history and ancestral history and underwent a physical examination. Women in the study group underwent biochemical testing and pelvic ultrasound examinations, and men underwent a semen analysis. RESULTS: Among the 125 couples tested, 8 c6uples (6.4%) displayed a balanced translocation, among which 7 (5.6%) showed a reciprocal translocation and 1 (0.8%) showed a Robertsonian translocation. All carriers of these translocations were aged <35 years. A significant proportion of carriers reported a poor obstetric history and a past fetal malformation. All male carriers had a normal semen analysis. CONCLUSION: Couples who experience ≥2 pregnancy losses of unknown origin should undergo a cytogenetic analysis, and findings showing a chromosomal abnormality in either parent must be followed by genetic counseling.