At a glance: the largest Niemann-Pick type C1 cohort with 602 patients diagnosed over 15 years.

Niemann-Pick type C1 disease (NPC1 [OMIM 257220]) is a rare and severe autosomal recessive disorder, characterized by a multitude of neurovisceral clinical manifestations and a fatal outcome with no effective treatment to date. Aiming to gain insights into the genetic aspects of the disease, clinical, genetic, and biomarker PPCS data from 602 patients referred from 47 countries and diagnosed with NPC1 in our laboratory were analyzed. Patients' clinical data were dissected using Human Phenotype Ontology (HPO) terms, and genotype-phenotype analysis was performed. The median age at diagnosis was 10.6 years (range 0-64.5 years), with 287 unique pathogenic/likely pathogenic (P/LP) variants identified, expanding NPC1 allelic heterogeneity. Importantly, 73 P/LP variants were previously unpublished. The most frequent variants detected were: c.3019C > G, p.(P1007A), c.3104C > T, p.(A1035V), and c.2861C > T, p.(S954L). Loss of function (LoF) variants were significantly associated with earlier age at diagnosis, highly increased biomarker levels, and a visceral phenotype (abnormal abdomen and liver morphology). On the other hand, the variants p.(P1007A) and p.(S954L) were significantly associated with later age at diagnosis (p < 0.001) and mildly elevated biomarker levels (p ≤ 0.002), consistent with the juvenile/adult form of NPC1. In addition, p.(I1061T), p.(S954L), and p.(A1035V) were associated with abnormality of eye movements (vertical supranuclear gaze palsy, p ≤ 0.05). We describe the largest and most heterogenous cohort of NPC1 patients published to date. Our results suggest that besides its utility in variant classification, the biomarker PPCS might serve to indicate disease severity/progression. In addition, we establish new genotype-phenotype relationships for "frequent" NPC1 variants.

GGPS1-associated muscular dystrophy with and without hearing loss.

Ultra-rare biallelic pathogenic variants in geranylgeranyl diphosphate synthase 1 (GGPS1) have recently been associated with muscular dystrophy/hearing loss/ovarian insufficiency syndrome. Here, we describe 11 affected individuals from four unpublished families with ultra-rare missense variants in GGPS1 and provide follow-up details from a previously reported family. Our cohort replicated most of the previously described clinical features of GGPS1 deficiency; however, hearing loss was present in only 46% of the individuals. This report consolidates the disease-causing role of biallelic variants in GGPS1 and demonstrates that hearing loss and ovarian insufficiency might be a variable feature of the GGPS1-associated muscular dystrophy.

Biallelic hypomorphic mutations in HEATR5B, encoding HEAT repeat-containing protein 5B, in a neurological syndrome with pontocerebellar hypoplasia.

HEAT repeats are 37-47 amino acid flexible tandem repeat structural motifs occurring in a wide variety of eukaryotic proteins with diverse functions. Due to their ability to undergo elastic conformational changes, they often serve as scaffolds at sites of protein interactions. Here, we describe four affected children from two families presenting with pontocerebellar hypoplasia manifest clinically with neonatal seizures, severe intellectual disability, and motor delay. Whole exome sequencing identified biallelic variants at predicted splice sites in intron 31 of HEATR5B, encoding the HEAT repeat-containing protein 5B segregating in a recessive fashion. Aberrant splicing was found in patient fibroblasts, which correlated with reduced levels of HEATR5B protein. HEATR5B is expressed during brain development in human, and we failed to recover live-born homozygous Heatr5b knockout mice. Taken together, our results implicate loss of HEATR5B in pontocerebellar hypoplasia.

Phenotypic and mutational spectrum of thirty-five patients with Sjögren-Larsson syndrome: identification of eleven novel ALDH3A2 mutations and founder effects.

Sjögren-Larsson syndrome (SLS) is a rare neurocutaneous disorder characterized by congenital ichthyosis, spastic diplegia and intellectual disability. It is an inborn error of lipid metabolism caused by biallelic mutations in the ALDH3A2 gene encoding the fatty aldehyde dehydrogenase that plays a pivotal role in metabolism of long-chain aliphatic aldehydes and alcohols. In this report, we describe the clinical, neuro-radiological and molecular findings of 35 patients with SLS. All patients shared the typical clinical manifestations of SLS including spasticity, ichthyosis and intellectual disability. Brain MRI demonstrated deep while matter affection in all patients that varied in severity. Mutational analysis of the ALDH3A2 gene revealed 16 distinct mutations including 11 previously unreported ones. Three mutations (p.S365L, p.R9* and p.G400R) were recurrent in our patients with frequencies ranging from 12 to 24%. Interestingly, patients carrying the two new mutations p.R9* and p.G400R shared similar haplotypes suggesting possible founder effects in our population. In conclusion, we present a large cohort of patients from the same ethnicity with the characteristic clinical and brain imaging findings of SLS but with variable inter and intra familial severity and expressivity. We also identified many novel and founder ALDH3A2 mutations thus expanding the mutational spectrum of the disorder.

Isolation of sinapic acid from broccoli using molecularly imprinted polymers.

A molecularly imprinted polymer was synthesized for the purpose of sinapic acid isolation from Egyptian nutraceutical Botrytis italica, L. (broccoli) due to its prominent medicinal and wide pharmacological activities. A computational study was first developed to determine the optimal template to functional monomer molar ratio. Based on the computational results, five polymers were synthesized using a bulk polymerization method with sinapic acid as the template molecule. Evaluation of the synthesized polymers binding performance was carried out using batch rebinding assay, which revealed that the molecularly imprinted polymer of molar ratio (1:4:20), template to functional monomer (4-vinyl pyridine) to crosslinker (ethylene glycol dimethacrylate) was of optimum performance, thus, this polymer was applied for sinapic acid isolation from closely related analogues. This represents a more practical approach to isolate sinapic acid from different natural extracts selectively.

Megalencephalic leukoencephalopathy with cysts in twelve Egyptian patients: novel mutations in MLC1 and HEPACAM and a founder effect.

Two genes causing megalencephalic leukoencephalopathy with subcortical cysts (MLC) have been discovered so far. Here, we identified MLC1 and HEPACAM mutations in ten and two patients, respectively. The molecular results included an unreported inframe duplication mutation (c.929_930dupCTGCTG; p.L309dup) of MLC1 and a novel missense mutation c.293G>A (p.R98H) of HEPACAM. Further, the previously reported missense (c.278C>T; p.S93L) and the deletion/insertion (c.908_918delinsGCA; p.V303Gfs*96) were found in one and 8 patients (75 %), respectively. The 8 patients carrying the p.V303Gfs*96 shared a similar haplotype suggesting a founder effect. All mutations were in the homozygous state proving the autosomal recessive mode of inheritance. The core phenotype of macrocephaly, subcortical cysts and white matter appeared homogeneous although the patients differed in the onset, clinical course, disease severity and brain imaging findings. Our study expands the spectrum of mutations in MLC1 and HEPACAM and supports the genetic and clinical heterogeneity. Further, It confirms c.908_918delinsGCA (p.V303Gfs*96) as a founder mutation among Egyptian patients. This finding will contribute to provide targeted testing for this mutation in MLC patients in our population.