Pathomorphological and biochemical alterations in Ehlers-Danlos-syndrome type IV

Enlarged Dural Sac in Idiopathic Bronchiectasis Implicates Heritable Connective Tissue Gene Variants

RATIONALE

Patients with idiopathic bronchiectasis are predominantly female and have an asthenic body morphotype and frequent nontuberculous mycobacterial respiratory infections. They also demonstrate phenotypic features (scoliosis, pectus deformity, mitral valve prolapse) that are commonly seen in individuals with heritable connective tissue disorders.

OBJECTIVES

To determine whether lumbar dural sac size is increased in patients with idiopathic bronchiectasis as compared with control subjects, and to assess whether dural sac size is correlated with phenotypic characteristics seen in individuals with heritable connective tissue disorders.

METHODS

Two readers blinded to diagnosis measured anterior-posterior and transverse dural sac diameter using L1-L5 magnetic resonance images of 71 patients with idiopathic bronchiectasis, 72 control subjects without lung disease, 29 patients with cystic fibrosis, and 24 patients with Marfan syndrome. We compared groups by pairwise analysis of means, using Tukey's method to adjust for multiple comparisons. Dural sac diameter association with phenotypic and clinical features was also tested.

MEASUREMENTS AND MAIN RESULTS

The L1-L5 (average) anterior-posterior dural sac diameter of the idiopathic bronchiectasis group was larger than those of the control group (P < 0.001) and the cystic fibrosis group (P = 0.002). There was a strong correlation between increased dural sac size and the presence of pulmonary nontuberculous mycobacterial infection (P = 0.007) and long fingers (P = 0.003). A trend toward larger dural sac diameter was seen in those with scoliosis (P = 0.130) and those with a family history of idiopathic bronchiectasis (P = 0.149).

CONCLUSIONS

Individuals with idiopathic bronchiectasis have an enlarged dural sac diameter, which is associated with pulmonary nontuberculous mycobacterial infection, long fingers, and family history of idiopathic bronchiectasis. These findings support our hypothesis that "idiopathic" bronchiectasis development reflects complex genetic variation in heritable connective tissue and associated transforming growth factor-β-related pathway genes.

Ehlers-Danlos Syndrome Type IV with Bilateral Pneumothorax

A 17-year-old teen was hospitalized with bilateral pneumothorax. After the bilateral lungs were expanded using catheter tubes, he fully recovered and he was discharged from our hospital. He had a history of colon perforation. Ehlers-Danlos syndrome (EDS) was suspected due to the combination of colon perforation and pneumothorax, and EDS type IV was confirmed after a genetic study identified a c.1511g>a mutation in the COL3A1 gene. This is the first report of bilateral pneumothorax caused by EDS type IV. Clinicians should consider EDS type IV in the differential diagnosis for bilateral pneumothorax in conjunction with distinct previous histories and radiological findings.

Hereditary equine regional dermal asthenia ('hyperelastosis cutis') in 50 horses: clinical, histological, immunohistological and ultrastructural findings

Data on fifty horses with hereditary equine regional dermal asthenia (HERDA; "hyperelastosis cutis") were collected on clinical, histopathological, ultrastructural and immunohistological findings. All horses were Quarter horses or of Quarter horse ancestry. Pedigree evaluation strongly supported an autosomal recessive mode of inheritance. The most common lesions were seromas/haematomas, open wounds, sloughing skin, and loose, easily tented skin that did not return to its initial position. Definitive diagnosis could not be made via histopathology, although the presence of tightly grouped thin and shortened collagen fibres arranged in clusters in the deep dermis was suggestive of the disease. Trichrome, acid orcein-Giemsa and immunohistochemical stains for collagens I and III showed no consistent abnormalities compared to control horses; an increase in elastic fibres was not a consistent finding. Electron microscopy showed no abnormalities in the periodicity of the collagen bundles; neither orientation nor variation of cross-section diameter of the collagen fibrils differentiated control from affected horses. The diagnosis of HERDA relies on clinical presentation, but may be supported by suggestive (although not pathognomonic) histopathological lesions.

Multiple vascular and bowel ruptures in an adolescent male with sporadic Ehlers-Danlos syndrome type IV

Ehlers-Danlos syndrome (EDS) type IV is a heritable disorder resulting from mutations in the COL3A1 gene that cause deficient production of type III collagen. Clinical manifestations of EDS type IV include hypermobility of small joints, excessive bruisability, thin translucent skin, poor wound healing, bowel rupture, and vascular rupture that is often fatal. A 14-year-old male without a family history of EDS died following multiple bowel and abdominal blood vessel ruptures. Even in areas apart from rupture sites, the bowel wall was thin because of diminished submucosa and muscularis propria. Similarly, the walls of blood vessels in bowel submucosa and elsewhere in the abdomen varied in thickness, and contained frayed and fragmented elastic tissue fibers. Fibroblasts cultured from the patient's skin secreted reduced quantities of type III collagen that was explained by a point mutation in one copy of the COL3A1 gene. EDS type IV should be strongly suspected in any patient with otherwise unexplainable bowel and/or vessel rupture.

Spontaneous rupture of liver in a patient with Ehlers Danlos disease type IV

Ehlers-Danlos syndrome (EDS) type IV is an autosomal dominant connective tissue disease caused by mutations in the type III collagen gene resulting in extreme tissue fragility. Affected individuals are at risk of dramatic and often fatal complications, mostly spontaneous arterial, uterine, or colonic ruptures. Phenotypic expression of EDS type IV is variable and clinical signs are generally quite subtle, thus making a prompt diagnosis difficult. The case of a 33-year-old woman is described who presented with a wide range of clinical features and sequelae that eventually led to the diagnosis of EDS type IV. She presented with spontaneous liver rupture, renal infarction, and pneumothorax, all representing rare complications of EDS type IV. Prior history revealed a uterine rupture in advanced pregnancy associated with ischemic necrosis of the descending and sigmoid colon. EDS type IV should be suspected in young individuals who present with such unusual complications. Early diagnosis is essential if severe or even lethal complications are to be avoided in the diagnostic and therapeutic management of such patients.

Abnormal extracellular matrix in Ehlers-Danlos syndrome type IV due to the substitution of glycine 934 by glutamic acid in the triple helical domain of type III collagen

A unique substitution of glycine 934 by glutamic acid in the triple helical domain of type III collagen was identified in a proband with Ehlers-Danlos syndrome type IV. The substitution was due to the transition of G 3302 to A in alpha 1(III) cDNA which is encoded by exon 46 of COL3A1. It resulted in a severe deficiency of type III collagen in fibroblast cultures and dermis. Dilatation of the endoplasmic reticulum of the dermal fibroblasts was probably due to the failure of these cells to secrete type III collagen molecules containing one or more mutant alpha 1(III) chains. The dermal collagen fibrils were narrow, but their constituent type III collagen molecules contained predominantly normal alpha 1(III) chains. As a results, the major effect of the substitution of glycine 934 by glutamic acid was to severely reduce the amount of normal type III collagen available for the formation of heterotypic collagen fibrils in the extracellular matrix.