Lysosomal storage disorders (LSD) are rare entities of recessive inheritance.

BackgroundAutosomal dominant mental retardation 21 (MRD21) is a very rare condition, characterized by short stature, microcephaly, mild facial dysmorphisms and intellectual disability that ranged from mild to severe. MRD21 is caused by mutations in CCCTC-binding factor (CTCF) and this was established through only four unrelated cases, two of which had frameshift mutations. CTCF is a master transcriptional regulator that controls chromatin structure and may serve as insulator and transcriptional activator and repressor.Case presentationThis study presents, clinically and molecularly, an Emirati patient with de novo frameshift mutation in CTCF. This novel mutation was uncovered using whole exome sequencing and was confirmed by Sanger sequencing in the trio. In silico analysis, using SIFT Indel, indicates that this frameshift; p.Lys206Profs*13 is functionally damaging with the likely involvement of nonsense-mediated mRNA decay.ConclusionsUpon comparing the clinical picture of the herewith-reported individual with previously reported cases of MRD21, there seems to be many common symptoms, and few new ones that were not observed before. This helps to further define this rare condition and its molecular underpinnings.

ECHS1 is a mitochondrial matrix enzyme that catalyzes an important step in the β-oxidation spiral of fatty acid catabolism, and individuals with mutations in the ECHS1 gene suffer from an autosomal recessive condition typified by delayed psychomotor development, mitochondrial encephalopathy, hypotonia, and cardiomyopathy. Here we report the first Arab case of ECHS1 Deficiency. The patient was born to consanguineous parents with all growth parameters being low for gestational age, and was persistently desaturated. Cord blood gas and later blood analysis showed severe metabolic acidosis. Tandem MS revealed increased levels of valine, and Leucine/Isoleucine and decreased level of Glutamine. There was also a large patent ductus arteriosus with right to left shunt and a possible small muscular ventricular septal defect. Whole Exome Sequencing revealed a novel homozygous missense mutation in the ECHS1 gene; c.842 A > G (p.Glu281Gly). In-silico analysis suggests that the residue affected by this mutation may be involved in an important functional or structural role.