PLOD1-related kyphoscoliotic Ehlers-Danlos syndrome (kEDS) is an autosomal recessive generalized connective tissue disorder characterized by hypotonia, early-onset kyphoscoliosis, and generalized joint hypermobility in association with skin fragility and ocular abnormality. Intelligence is normal. Life span may be normal, but affected individuals are at risk for rupture of medium-sized arteries. Adults with severe kyphoscoliosis are at risk for complications from restrictive lung disease, recurrent pneumonia, and cardiac failure.

Brittle cornea syndrome (BCS) is characterized by blue sclerae, corneal rupture after minor trauma, keratoconus or keratoglobus, hyperelasticity of the skin, and hypermobility of the joints (Al-Hussain et al., 2004). It is classified as a form of Ehlers-Danlos syndrome (Malfait et al., 2017). Genetic Heterogeneity of Brittle Cornea Syndrome Brittle cornea syndrome-2 (BCS2; 614170) is caused by mutation in the PRDM5 gene (614161) on chromosome 4q27.

ATP6V0A2-related cutis laxa is characterized by generalized cutis laxa, findings associated with generalized connective tissue disorder, developmental delays, and a variety of neurologic findings including abnormality on brain MRI. At birth, hypotonia, overfolded skin, and distinctive facial features are present and enlarged fontanelles are often observed. During childhood, the characteristic facial features and thick or coarse hair may become quite pronounced. The skin findings decrease with age, although easy bruising and Ehlers-Danlos-like scars have been described in some. In most (not all) affected individuals, cortical and cerebellar malformations are observed on brain MRI. Nearly all affected individuals have developmental delays, seizures, and neurologic regression.

The Richieri-Costa/Guion-Almeida syndrome is characterized by mild mental retardation, short stature, microbrachycephaly, ptosis, esotropia, cleft lip/palate (Richieri-Costa and Guion-Almeida, 1992).

Beare-Stevenson cutis gyrata syndrome (BSTVS) is an autosomal dominant condition characterized by the furrowed skin disorder of cutis gyrata, acanthosis nigricans, craniosynostosis, craniofacial dysmorphism, digital anomalies, umbilical and anogenital abnormalities, and early death (summary by Przylepa et al., 1996).

Noonan syndrome (NS) is characterized by characteristic facies, short stature, congenital heart defect, and developmental delay of variable degree. Other findings can include broad or webbed neck, unusual chest shape with superior pectus carinatum and inferior pectus excavatum, cryptorchidism, varied coagulation defects, lymphatic dysplasias, and ocular abnormalities. Although birth length is usually normal, final adult height approaches the lower limit of normal. Congenital heart disease occurs in 50%-80% of individuals. Pulmonary valve stenosis, often with dysplasia, is the most common heart defect and is found in 20%-50% of individuals. Hypertrophic cardiomyopathy, found in 20%-30% of individuals, may be present at birth or develop in infancy or childhood. Other structural defects include atrial and ventricular septal defects, branch pulmonary artery stenosis, and tetralogy of Fallot. Up to one fourth of affected individuals have mild intellectual disability, and language impairments in general are more common in NS than in the general population.

SADDAN dysplasia (severe achondroplasia with developmental delay and acanthosis nigricans) is a very rare skeletal dysplasia characterized by the constellation of these features. Radiology reveals 'ram's horn' shaped clavicles and reverse bowing of lower limbs. Approximately half of patients die before the fourth week of life secondary to respiratory failure (summary by Zankl et al., 2008).

Noonan syndrome (NS) is characterized by characteristic facies, short stature, congenital heart defect, and developmental delay of variable degree. Other findings can include broad or webbed neck, unusual chest shape with superior pectus carinatum and inferior pectus excavatum, cryptorchidism, varied coagulation defects, lymphatic dysplasias, and ocular abnormalities. Although birth length is usually normal, final adult height approaches the lower limit of normal. Congenital heart disease occurs in 50%-80% of individuals. Pulmonary valve stenosis, often with dysplasia, is the most common heart defect and is found in 20%-50% of individuals. Hypertrophic cardiomyopathy, found in 20%-30% of individuals, may be present at birth or develop in infancy or childhood. Other structural defects include atrial and ventricular septal defects, branch pulmonary artery stenosis, and tetralogy of Fallot. Up to one fourth of affected individuals have mild intellectual disability, and language impairments in general are more common in NS than in the general population.

Noonan syndrome (NS) is characterized by characteristic facies, short stature, congenital heart defect, and developmental delay of variable degree. Other findings can include broad or webbed neck, unusual chest shape with superior pectus carinatum and inferior pectus excavatum, cryptorchidism, varied coagulation defects, lymphatic dysplasias, and ocular abnormalities. Although birth length is usually normal, final adult height approaches the lower limit of normal. Congenital heart disease occurs in 50%-80% of individuals. Pulmonary valve stenosis, often with dysplasia, is the most common heart defect and is found in 20%-50% of individuals. Hypertrophic cardiomyopathy, found in 20%-30% of individuals, may be present at birth or develop in infancy or childhood. Other structural defects include atrial and ventricular septal defects, branch pulmonary artery stenosis, and tetralogy of Fallot. Up to one fourth of affected individuals have mild intellectual disability, and language impairments in general are more common in NS than in the general population.

Periodontal Ehlers-Danlos syndrome (pEDS) is characterized by distinct oral manifestations. Periodontal tissue breakdown beginning in the teens results in premature loss of teeth. Lack of attached gingiva and thin and fragile gums lead to gingival recession. Connective tissue abnormalities of pEDS typically include easy bruising, pretibial plaques, distal joint hypermobility, hoarse voice, and less commonly manifestations such as organ or vessel rupture. Since the first descriptions of pEDS in the 1970s, 148 individuals have been reported in the literature; however, future in-depth descriptions of non-oral manifestations in newly diagnosed individuals with a molecularly confirmed diagnosis of pEDS will be important to further define the clinical features.

Noonan syndrome (NS) is characterized by characteristic facies, short stature, congenital heart defect, and developmental delay of variable degree. Other findings can include broad or webbed neck, unusual chest shape with superior pectus carinatum and inferior pectus excavatum, cryptorchidism, varied coagulation defects, lymphatic dysplasias, and ocular abnormalities. Although birth length is usually normal, final adult height approaches the lower limit of normal. Congenital heart disease occurs in 50%-80% of individuals. Pulmonary valve stenosis, often with dysplasia, is the most common heart defect and is found in 20%-50% of individuals. Hypertrophic cardiomyopathy, found in 20%-30% of individuals, may be present at birth or develop in infancy or childhood. Other structural defects include atrial and ventricular septal defects, branch pulmonary artery stenosis, and tetralogy of Fallot. Up to one fourth of affected individuals have mild intellectual disability, and language impairments in general are more common in NS than in the general population.