Clinical Description
Arterial tortuosity syndrome (ATS) is characterized by widespread elongation and tortuosity of the aorta and mid-sized arteries as well as focal stenosis of segments of the pulmonary arteries and/or aorta combined with findings of a generalized connective tissue disorder.
ATS is a highly variable disorder ranging from early mortality during infancy to limited manifestations in adulthood [Pletcher et al 1996, Callewaert et al 2008, Castori et al 2012, Beyens et al 2018].
Most affected individuals are identified in early childhood, often because of a cardiac murmur or cyanosis. Subsequently manifestations of a generalized connective tissue disorder are often observed, prompting an echocardiogram that reveals aortic abnormalities with or without pulmonary artery stenosis.
About 12% of all affected individuals are admitted to the neonatal intensive care unit because of a primary presentation with infant respiratory distress syndrome. Underlying causes may be diverse and include insufficient lung maturation, pulmonary hypertension, and/or diaphragmatic hernia.
Few reports mention cardiorespiratory failure as the initial presentation during infancy or young childhood.
Cutaneous (cutis laxa, stretchable skin) and gastrointestinal (pyloric stenosis, failure to thrive) manifestations have been infrequently reported as the initial presenting symptoms.
Rare patients have been identified initially in adulthood, with joint aches and premature aging as the main presenting features [
Castori et al 2012].
To date, 106 individuals with ATS and biallelic pathogenic variants in SLC2A10 have been identified [Beyens et al 2018, de Marcellus et al 2018, Kocova et al 2018, Zoma et al 2019]. The following description of the phenotypic features associated with this condition is based on these reports.
Table 2.
Arterial Tortuosity Syndrome (ATS): Frequency of Select Features
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Feature | % of Persons w/Feature 1 | Comment |
---|
Cardiovascular findings
| Aortic tortuosity | 92% | |
Tortuosity of other arteries | 80% | |
Aortic root aneurysm | 16% | Aggressive in young childhood or slowly progressive in adolescence/adulthood |
Pulmonary artery stenosis | 57% | |
Aortic stenosis | 24% | |
Other arterial stenosis | 15% | |
Autonomic dysfunction | 18% | |
Craniofacial features
| Characteristic facial features | ~60% | Overall estimate, mainly based on authors' personal experience |
Long face | 73% | |
Downslanted palpebral fissures | 42% | |
Convex nasal ridge | 37% | |
Full cheeks | 54% | |
Micrognathia | 58% | |
High palate | 49% | |
Cleft palate / bifid uvula | 7% | |
Findings of
generalized
connective
tissue disorder
| Joint hypermobility | 76% | |
Joint pain | 26% | Progressive w/age |
Cutis laxa | 31% | |
Inguinal hernia | 38% | |
Diaphragmatic/sliding hernia | 29% | |
Skeletal
findings
| Pectus deformity | 28% | |
Arachnodactyly | 30% | |
Scoliosis | 22% | |
Eye findings
| Keratoconus | 15% | Recent finding; # of persons assessed in detail is limited. Prevalence may be ↑ in young adults. |
Myopia | 43% | |
Other
| Respiratory tract | 15% | |
Urogenital anomalies | 20% | |
Cardiovascular involvement. The cardiovascular system is the major source of morbidity and mortality. Cardiovascular manifestations include congenital widespread tortuosity of the large and mid-sized arteries. There is increased risk at any age for aneurysm formation and dissection both at the aortic root and throughout the arterial tree [Pletcher et al 1996, Wessels et al 2004, Drera et al 2007a, Callewaert et al 2008, Castori et al 2012]. Although aortic dissections have been mainly reported in early clinically diagnosed cases [Pletcher et al 1996, Wessels et al 2004], some of which had molecular genetic confirmation later [Coucke et al 2006], no dissections have been reported since the initial publication of the causative gene [Coucke et al 2006]. Nevertheless, aggressive aortic root dilatation has been reported in infancy and young childhood [Beyens et al 2018]. Arterial aneurysms are amenable to surgery [Bottio et al 2007] (see Management).
The risk is also increased at any age for ischemic vascular events involving cerebrovascular circulation (resulting in non-hemorrhagic stroke) and the abdominal arteries (resulting in infarctions of abdominal organs). Although arterial dissections have been reported, it is unclear if thrombosis due to endothelial damage caused by increased shear stress on the wall of the tortuous arteries may have precipitated some of these ischemic events.
Focal stenoses of the aorta and aortic branches are congenital and amenable to treatment (see Management). In addition, long stenotic stretches of the aorta may occur.
Hypertension and ventricular hypertrophy have been reported in individuals and may require aggressive management [Beyens et al 2018, de Marcellus et al 2018]. Increased media thickness and arterial stiffness (as indicated by increased pulse wave velocity) may be associated [de Marcellus et al 2018].
Stenosis of the main and peripheral pulmonary arteries may lead to pulmonary hypertension [Wessels et al 2004, Callewaert et al 2008, Beyens et al 2018].
Large-vein dilatation [Callewaert et al 2008, Beyens et al 2018] or in some cases tortuosity [Moceri et al 2013] may be present.
Valvular regurgitation and mitral valve prolapse [Drera et al 2007b, Callewaert et al 2008, Castori et al 2012, Beyens et al 2018] have been reported.
A higher rate of Raynaud phenomenon and orthostatic hypotension is reported; the causal relation remains to be established [Callewaert et al 2008, Beyens et al 2018].
Craniofacial involvement. Typical facial characteristics (see ) can be present from early childhood, but usually become more prominent in older children and adults.
Generalized connective tissue disorder. The skin is usually soft and loose in ATS. Some affected individuals have a hyperextensible skin and rarely may present with frank cutis laxa [Callewaert et al 2008, Beyens et al 2018].
Individuals often present with hypotonia and joint hypermobility and are at risk for sprains and luxations. Adults are at increased risk for joint pain and fatigue [Castori et al 2012].
Diaphragmatic hernia and sliding hiatal hernias are reported in up to 50% of affected individuals [Callewaert et al 2008, Zaidi et al 2009].
Affected women are more prone to prolapse of the bladder, uterus, and rectum, especially following childbirth [Castori et al 2012].
Skeletal findings. Growth of the long bones may be excessive. Although clear dolichostenomelia (disproportionately long arms and legs compared to the trunk) is rarely present, overgrowth of the ribs may result in pectus deformity, and the hands often show arachnodactyly. Scoliosis is rare and ranges from mild to severe; it can be progressive, mostly during periods of fast growth. Pes planus with hindfoot valgus may be present. Knee and/or elbow contractures and camptodactyly have been reported.
Osteopenia has been observed in rare individuals [Authors, unpublished data].
Eye. Thin corneas and/or pellucid marginal degeneration of the corneas were present in five children assessed in detail [Hardin et al 2018]. Keratoconus has been reported in eight affected individuals, two of whom also had keratoglobus and deep corneal opacification [Callewaert et al 2008, Hasler et al 2011, Hardin et al 2018]. Note that the corneal findings become more pronounced with age, and that many children have not been assessed properly to identify corneal thinning (which often precedes keratoconus). Ectopia lentis has not been described. It is unclear whether myopia and astigmatism occur more frequently than in the general population.
Other
Respiratory tract. Infants may present with infant respiratory stress syndrome, requiring admission to a neonatal intensive care unit. Pulmonary hypertension may cause shortness of breath, fatigue, and cyanotic episodes. Single cases of early-onset emphysema [
Takahashi et al 2013] and pneumonia [
Wessels et al 2004] have been described, but it is unclear if individuals with ATS are truly at risk for these features.
Urogenital anomalies. Pyeloectasia and bladder diverticula have been reported in multiple individuals. Hypospadias, urine retention, and hematuria (underlying cause unknown) were each reported in single individuals.
Life span. Although early reports mentioned 40% mortality before age four years [Wessels et al 2004], larger series of individuals with a molecularly confirmed diagnosis indicate a milder disease spectrum [Callewaert et al 2008, Beyens et al 2018]. It is likely some individuals in whom the diagnosis was not molecularly confirmed had a similar disorder with a poorer prognosis – including EFEMP2-related cutis laxa (see Differential Diagnosis). The earlier literature may also have been biased toward reporting the more severe end of the phenotypic spectrum.