Search

Identification of the first pathogenic branch point variant in the SMS gene in a large French non-consanguineous family with a phenotype retrospectively consistent with Snyder-Robinson syndrome. RT-PCR analysis followed by RNA-sequencing demonstrated that this variant, lead to the synthesis of a predominant aberrant transcript with complete intron 6 retention., (© 2024 The Author(s). Clinical Genetics published by John Wiley & Sons Ltd.)

Glutathione synthetase deficiency is a rare inborn metabolic disease usually caused by biallelic variants in GSS. Clinical severity varies from isolated hemolytic anemia, sometimes associated with chronic metabolic acidosis and 5-oxoprolinuria, to severe neurological phenotypes with neonatal lethality. Here we report on two fetal siblings from two pregnancies with glutathione synthetase deficiency exhibiting similar multiple congenital anomalies associating phocomelia, cleft palate, intra-uterine growth retardation, genito-urinary malformations, and congenital heart defect. Genome sequencing showed that both fetuses were compound heterozygous for two GSS variants: the previously reported pathogenic missense substitution NM_000178.4 c.800G>A p.(Arg267Gln), and a 2.4 kb intragenic deletion NC_000020.11:g.34944530_34946833del. RNA-seq on brain tissue revealed the out-of-frame deletion of the exon 3 and an almost monoallelic expression of the missense variant (88%), suggesting degradation of the deletion-harboring allele by nonsense-mediated mRNA decay. 5-oxoproline (pyroglutamic acid) levels in amniotic fluid were elevated, suggesting an alteration of the gamma-glutamyl cycle, and corroborating the pathogenicity of the two GSS variants. Only one case of glutathione synthetase deficiency with limb malformations has previously been reported, in a newborn homozygous for the c.800G>A variant. Thus, our data allow us to discuss a potential phenotypic extension of glutathione synthetase deficiency, with a possible involvement of the c.800G>A variant., (© 2024 The Author(s). Clinical Genetics published by John Wiley & Sons Ltd.)

Dehydrated hereditary stomatocytosis (DHS) (MIM#194380) is a rare autosomal dominant disorder of red blood cell permeability, characterized by a partially or fully compensated nonimmune hemolytic anemia. PIEZO1 is the major gene involved with hundreds of families described, some of which present transient perinatal edema of varying severity. A smaller subset of individuals harbors pathogenic variants in KCNN4, sometimes referred as "Gardos channelopathy." Up to now, only six pathogenic variants in KCNN4 have been reported in 13 unrelated families. Unlike PIEZO1-DHS, neither perinatal edema nor fetal loss has ever been observed linked to KCNN4-DHS. We report the first fetal loss due to non-immune hydrops fetalis related to a pathogenic 28 bp deletion (NM_002250.2: c.1109_1119+17del) in KCNN4. This observation underlies the need for very close monitoring of pregnancies when one parent is affected by DHS regardless of genotype (PIEZO1 or KCNN4)., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)