To describe the clinical and molecular characteristics of patients with very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. Methods: A retrospective observational cross-sectional analysis was conducted on all patients with VLCAD deficiency at (Genetic/Metabolic Section), Prince Sultan Military Medical City (PSMMC), Riyadh, Saudi Arabia from 2000 to 2019. Demographic, clinical, and laboratory data were abstracted from the electronic hospital records using a case report form. Results: A total of 14 children were analyzed. Six presented with hypoglycemia, 4 with cardiomyopathy, and 10 had rhabdomyolysis. Five patients had early onset severe phenotype, while 9 had mild form. The molecular study revealed homozygous mutations in ACADVL in all 14 patients. Three variants were not reported before. All patients were treated with medium-chain triglyceride and carnitine. Ten patients are alive and have normal development, while 4 died. Conclusion: Most of the patients in this cohort presented in the neonatal period either by newborn screening or clinically with hypoglycemia, cardiomyopathy, and rhabdomyolysis. The new molecular variants detected in this study broaden the genetic spectrum of VLCAD deficiency in Saudi Arabia.

Background: Classic homocystinuria (HCU) is a rare inborn metabolic disease that is generally asymptomatic at birth. If untreated, it can cause a wide range of complications including intellectual disability, lens dislocation, and thromboembolism. This study aimed to describe the natural history and the molecular findings of patients with HCU, and to assess the importance of early diagnosis.Methods: This study retrospectively collected data on patients attending the metabolic unit at Prince Sultan Military Medical City, Riyadh, Saudi Arabia from 2011 to 2024. Demographic, clinical, and molecular data was extracted from the electronic medical records.Results: Among the 33 patients with HCU enrolled, 5/33 (15%) were diagnosed by newborn screening and the rest were diagnosed on clinical grounds. The complication profile was vast, with neuropsychiatric, musculoskeletal, ophthalmic, and thromboembolic morbidities complicating the disease course in 28/33 (85%) of the patients. None of the newborn screened patients had complications while all of the non‐newborn screened patients had at least one complication, p < 0.0001. The majority of parents in this cohort were highly consanguineous, with 90% had first or second cousin marriage. Seven previously reported variants were detected in this cohort and one novel variant was found in three patients (c.828+2‐828+ 3 delins ACACTTGCATCC, p.?). The known pathogenic variant (c.969G>A, p. (Trp323*)) was seen in most of the patients, with all of them coming from one tribe.Conclusions: This cohort gives further evidence that the newborn screening for HCU is likely to prevent the complications associated with the disease at least in the first few years of life. Therefore, newborn screening for HCU should be encouraged. Our molecular studies revealed the presence of a founder variant, detected in patients from a single tribe. This suggests that specific mutation testing may be cost‐effective for individuals from certain ethnicities.

Niemann–Pick disease type C (NPC) is an autosomal recessive lipid storage disorder. There are two types, NPC1, which is the predominant form (95%), and the rare NPC2, which represents less than 5% of the reported cases. Niemann–Pick disease type C2 usually presents with respiratory symptoms, cholestasis, neurological impairment, and hepatosplenomegaly. Case report: Here, we report a 3-year-old boy who presented to our hospital with exacerbation of chronic lung disease requiring invasive ventilatory support. He was previously diagnosed with interstitial lung disease. His parents used to instill olive oil in his nose (a few drops in each nostril daily for several months) to treat frequent nasal bleeding. A detailed history revealed prolonged neonatal jaundice for four months, with hepatosplenomegaly. In his second year, generalized hypotonia and delayed psychomotor development were observed. Upon presentation to our institute, chest CT showed evidence of intraparenchymal fat; therefore, lipoid pneumonia and lipid storage disease were suspected. The bronchoalveolar lavage results suggested pulmonary alveolar proteinosis (PAP). Whole-exome sequencing (WES) revealed a class one homozygous pathogenic variant in the NPC2 gene. Our patient faced a range of difficulties, including prolonged mechanical ventilation and diagnostic and therapeutic challenges. Conclusion: Niemann–Pick disease type C2 is a progressive and lethal condition that requires a high index of suspicion to pinpoint the diagnosis. Gene study remains the method of choice to confirm the diagnosis. There are limited choices of therapeutic interventions; therefore, genetic counseling and the prevention of recurrence should be the ultimate goal for affected families.

Desanto-Shinawi syndrome (DESSHS) is a rare autosomal dominant disorder caused by a loss of function variant or deletion of the WAC gene. DESSHS is characterized by dysmorphic features and global developmental delay. In this report, we discuss three boys with DESSHS. These three patients exhibited the characteristic facial dysmorphism, intellectual disability, and behavioral problems associated with DESSHS. In addition, the patients presented with features not previously associated with DESSHS, including choanal atresia, flat feet, hypospadias, caudothalamic groove, and periventricular leukomalacia. Two of our patients had novel sequence variants (de-novo) in the WAC gene, specifically c.921del (p. E307Dfs*24) and c.479delC (p. Pro160fs*32). The third variant was a 9,389 kbp deletion on chromosome 10p12.31p11.22, resulting in the deletion of 74 genes, including the WAC gene. This report highlights manifestations not previously reported with DESSHS and may expand the understanding of this rare disorder. Furthermore, two new variants were detected in our patients.

Homozygous achondroplasia, due to biallelic pathogenic FGFR3 variants, is the homozygous lethal expression of an autosomal dominant skeletal dysplasia and is clinically distinct from the classical heterozygous form. We describe a male infant born to two achondroplastic heterozygous parents with severe rhizomelic shortening and radiographic features typical of homozygous achondroplasia. Molecular analysis revealed a homozygous c.1138G>A (p.Gly380Arg) variant in FGFR3. The infant developed progressive respiratory compromise and died at 63 days of age due to pulmonary hypoplasia-related respiratory failure.