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Ehlers Danlos syndrome musculocontractural type (mcEDS) is a rare hereditary connective tissue disorder caused by biallelic pathogenic variants in the CHST14 or dermatan sulfate (DS) epimerase genes resulting in defective DS biosynthesis. It is characterized by congenital malformations and contractures, distinctive facial features and multisystemic fragility-related complications. To date, less than 100 patients with mcEDS have been reported. Vascular complications remain the major morbidity and may lead to mortality in the affected individuals. In this clinical report, we report on a currently 12-year-old boy with a novel homozygous CHST14 variant who presented with typical mcEDS symptoms and subsequently developed a life-threatening subcutaneous skull hematoma following a minor trauma, which required intensive care unit admission and surgical drainage along with several blood transfusions. This case expands the clinical and genetic spectrum of CHST14-related mcEDS which is essential for providing accurate prognosis, management and genetic counseling.

Ehlers Danlos syndrome musculocontractural type (mcEDS) is a rare hereditary connective tissue disorder caused by biallelic pathogenic variants in the CHST14 or dermatan sulfate (DS) epimerase genes resulting in defective DS biosynthesis. It is characterized by congenital malformations and contractures, distinctive facial features and multisystemic fragility-related complications. To date, less than 100 patients with mcEDS have been reported. Vascular complications remain the major morbidity and may lead to mortality in the affected individuals. In this clinical report, we report on a currently 12-year-old boy with a novel homozygous CHST14 variant who presented with typical mcEDS symptoms and subsequently developed a life-threatening subcutaneous skull hematoma following a minor trauma, which required intensive care unit admission and surgical drainage along with several blood transfusions. This case expands the clinical and genetic spectrum of CHST14-related mcEDS which is essential for providing accurate prognosis, management and genetic counseling. [ABSTRACT FROM AUTHOR]

ABSTRACT Bi-allelic variants in CHST14, encoding dermatan 4- O-sulfotransferase-1 (D4ST1), cause musculocontractural Ehlers-Danlos syndrome (MC-EDS), a recessive disorder characterized by connective tissue fragility, craniofacial abnormalities, congenital contractures, and developmental anomalies. Recently, the identification of bi-allelic variants in DSE, encoding dermatan sulfate epimerase-1 (DS-epi1), in a child with MC-EDS features, suggested locus heterogeneity for this condition. DS-epi1 and D4ST1 are crucial for biosynthesis of dermatan sulfate (DS) moieties in the hybrid chondroitin sulfate (CS)/DS glycosaminoglycans (GAGs). Here, we report four novel families with severe MC-EDS caused by unique homozygous CHST14 variants and the second family with a homozygous DSE missense variant, presenting a somewhat milder MC-EDS phenotype. The glycanation of the dermal DS proteoglycan decorin is impaired in fibroblasts from D4ST1- as well as DS-epi1-deficient patients. However, in D4ST1-deficiency, the decorin GAG is completely replaced by CS, whereas in DS-epi1-deficiency, still some DS moieties are present. The multisystemic abnormalities observed in our patients support a tight spatiotemporal control of the balance between CS and DS, which is crucial for multiple processes including cell differentiation, organ development, cell migration, coagulation, and connective tissue integrity. [ABSTRACT FROM AUTHOR]

Musculocontractural Ehlers-Danlos syndrome (mcEDS) is an autosomal recessive condition characterized by distinct craniofacial features, multisystem congenital malformations and progressive fragility of connective tissues. It is caused by pathogenic variants in CHST14 and DSE genes. There are three reports of pathogenic variants in DSE in four mcEDS patients. In this study we provide clinical and molecular presentation of two new patients with DSE related mcEDS. Analysing clinical exome data, a homozygous pathogenic DSE variant, c.1150_1157del p.(Pro384Trpfs*9), was identified in a 32 year old man with bilateral congenital talipes equinovarus, characteristic facial features, myopia, hyperextensible skin at the elbows, significant palmar wrinkling, bilateral inguinal hernias and chronic leg, back and joint pain. Electron microscopical examination of skin biopsy showed changes consistent with mild compensatory elastic fibre hypertrophy and mildly loose collagen bundles. The variant is predicted to result in a frameshift and introduction of a premature termination codon in the final exon of the DSE gene, anticipated to lead to the loss of approximately 60% of the normal reading frame. The second patient has a phenotype consistent with previously reported cases of DSE associated musculocontractural EDS. A novel homozygous missense DSE variant of uncertain clinical significance was detected. This case study further delineates the DSE associated mcEDS phenotype and illustrates absence of major cutaneous, cardiovascular, renal and respiratory features, which supports previous suggestions that patients with DSE associated mcEDS present with a milder phenotype compared to those with CHST14 mutations. [ABSTRACT FROM AUTHOR]