Marshall syndrome and a defect at the COL11A1 locus

Audiologic Manifestations of Marshall Syndrome

OBJECTIVE

Marshall syndrome is a genetic disorder caused by mutations in the COL11A1 gene. This syndrome is characterized by skeletal, ophthalmologic, craniofacial, and auditory abnormalities. Hearing loss is among the main manifestations reported in this disorder being observed in approximately 80% of affected individuals.The present study aims to describe the audiologic characteristics of three members of a family with Marshall syndrome and also serves as a review of the literature.

STUDY DESIGN

Family study.

SETTING

Tertiary care otology and skull base center.

PATIENTS

We report the audiologic findings in a family with Marshall syndrome consisting of a mother and her son and daughter.

INTERVENTION(S)

The audiologic evaluation included tympanometry, acoustic reflexes testing, auditory brainstem response, transient otoacoustic emissions, pure-tone audiometry, speech audiometry in quiet, and conditioned play audiometry. These methods were applied according to the age of the patients. In addition, we provide a review of the English-language literature in an attempt to clarify the auditory phenotype of this syndrome.

RESULTS

All 3 affected individuals had heterozygous c.3816+1G>A mutation in the splicing donor site of intron 50 of the COL11A1 gene. All three patients in our study had bilateral sensorineural hearing loss. Hearing impairment ranged from mild to moderate in the daughter, moderate in the son, and from mild to moderate in their mother.

CONCLUSION

The majority of individuals with Marshall syndrome present early-onset bilateral sensorineural hearing loss. Hearing impairment is usually detected in early childhood, progresses gradually, and becomes stable in late adulthood, with a severity ranging from mild to severe.

Stickler syndrome in children: a radiological review

AIM

To review the radiological findings of the largest cohort to date of paediatric patients with Stickler syndrome, all with confirmed molecular genetic analysis and sub-typing.

PATIENTS AND METHODS

It is understood that the National Health Service (NHS) commissioned service at Addenbrookes Hospital, Cambridge, UK has the largest cohort of Stickler syndrome patients in the paediatric age group worldwide with 240 registered children. Fifty-nine were assessed radiologically and for their genotypes. These radiographs were reviewed and 74 knee, 45 pelvic, and 47 spinal examinations were evaluated.

RESULTS

Radiological features were noted in 45.9% of knee radiographs, 11.1% of pelvic radiographs, and 42.6% of spinal radiographs. The findings were reviewed in the light of each patient's specific genetic Stickler syndrome subtype.

CONCLUSION

The prevalence of orthopaedic abnormalities overall in the present series is substantially below those published in previous smaller case series. This would support the more recent findings of an array of ocular only phenotypes of Stickler syndrome described in the literature.

Marshall syndrome: further evidence of a distinct phenotypic entity and report of new findings

Marshall syndrome and type II Stickler syndrome are caused by mutations in COL11A1, which codes for the proα1chain of collagen XI. Collagen XI is a minor fibrillar collagen co-expressed with collagen II in cartilage and the vitreous of the eye. Characteristic features of Marshall syndrome include midfacial hypoplasia, high myopia, and sensorineural-hearing deficit. Deletions, insertions, splice site, and missense mutations in COL11A1 have been identified in Stickler syndrome and Marshall syndrome patients. In this study, we describe the clinical presentations of seven patients with Marshall syndrome from three unrelated Saudi families, inherited as autosomal dominant (two families) and autosomal recessive (one family). Cardinal clinical features of Marshall syndrome are manifested in all patients. One patient had ectodermal abnormalities. Mutations (c.2702G > A in exon 34,IVS50 + 1G > A, and IVS50 + lG > C) were identified in COL11A1 in affected members. Interestingly, the first report of autosomal recessive Marshall syndrome was from Saudi Arabia caused by the same mutation (c.2702G > A, p.Gly901Glu) as in one of our families. This study depicts detailed phenotypic and genetic description of dominant and recessive forms of Marshall syndrome due to COL11A1 mutations.

TTF-2 stimulates expression of 17 genes, including one novel thyroid-specific gene which might be involved in thyroid development

Thyroid dysgenesis is the most frequent cause of congenital hypothyroidism, but its molecular pathophysiology is largely unknown. Our hypothesis that some genes downstream to thyroid transcription factor-2 (TTF-2) might be responsible for development of the thyroid prompted us to identify genes whose expression is stimulated by TTF-2. PCR products of cDNA clones obtained by a subtraction PCR method in TTF-2 expressing cell lines were screened with labeled cDNA by microarray analysis. We isolated 17 genes up-regulated by TTF-2, which were subsequently confirmed by quantitative reverse transcription-polymerase chain reaction (RT-PCR). One of them is a novel gene designated T1560 that showed a highly thyroid-specific expression pattern. Luciferase reporter assays showed that expression of all of the 14 genes tested was stimulated by both TTF-2 and TTF-1, another thyroid-specific transcription factor. Our results have important implications for understanding normal thyroid development as well as the molecular defects underlying thyroid dysgenesis.

Skeletal dysplasias and the osteoarthritic phenotype

In contrast to late-onset osteoarthritis (OA), the appearance of precocious OA has historically been recognized as a particularly aggressive form of the disorder that is frequently inherited as a Mendelian trait. In general, precocious OA appears as a consequence of many skeletal dysplasias, which, although individually rare, comprise a sizable population of patients when viewed in toto. In these patients the disease is often rapidly progressive and includes features of articular and extra-articular involvement that are not typical of classic OA. The molecular pathology of the chondro-osseous disorders has been the focus of intense study in recent years, with the promise of providing insight into skeletal development and homeostasis, as well as the aetiology and pathogenesis of degenerative joint disease.

Snowflake vitreoretinal degeneration

PURPOSE

The ocular findings, systemic features, and genetic loci distinguishing known genetic causes of vitreoretinal degenerations were studied in the original Snowflake family.

DESIGN

Prospective, comparative study and molecular genetic investigation.

PARTICIPANTS

Members of the original snowflake vitreoretinal degeneration family.

METHODS

Clinical data were collected on 26 family members by history and examination. Thirteen of the 26 total family members underwent prospective examination. Linkage to known vitreoretinal degeneration loci (COL2A1, COL11A1, and the Wagner disease locus) was evaluated with short tandem repeat markers.

MAIN OUTCOME MEASURES

Ocular and systemic features of known vitreoretinal degenerations.

RESULTS

Six of the 13 prospectively examined subjects had snowflake vitreoretinal degeneration. Corneal guttae (4/5; 80%), early onset cataract (5/6; 83%), fibrillar vitreous degeneration (6/6; 100%), and peripheral retinal abnormalities (5/6; 83%), including minute crystallinelike deposits called snowflakes (4/6; 67%), were common. Retinal detachment was seen in 1 of 6 of these prospectively examined subjects (17%). A total of 14 affected subjects were identified within the family, and in 3 (21%), retinal detachment developed. Orofacial features, early-onset hearing loss, and arthritis typical of Stickler syndrome were absent. Linkage to known vitreoretinal degeneration loci was excluded.

CONCLUSIONS

The absence of vitreous gel in the retrolental space and presence of fibrillar vitreous degeneration were consistent with the vitreous structure reported for collagen 11A1 (COL11A1) but not collagen 2A1 (COL2A1) mutations. The absence of systemic features was characteristic of the vitreoretinopathies linked to chromosome 5q13 (Wagner disease and erosive vitreoretinopathy) and mutations in exon 2 of the COL2A1 gene. Snowflakes in the peripheral retina and the absence of nyctalopia, posterior chorioretinal atrophy, and tractional retinal detachment were inconsistent with the chromosome 5q13 vitreoretinopathies. The association of Fuchs' corneal endothelial dystrophy found in this family has not been reported previously in other vitreoretinal degenerations. These findings and the exclusion of known genetic loci suggest snowflake is a distinct vitreoretinal degeneration.

Clinical and Molecular genetics of Stickler syndrome

Stickler syndrome is an autosomal dominant disorder with characteristic ophthalmological and orofacial features, deafness, and arthritis. Abnormalities of vitreous gel architecture are a pathognomonic feature, usually associated with high myopia which is congenital and non-progressive. There is a substantial risk of retinal detachment. Less common ophthalmological features include paravascular pigmented lattice degeneration and cataracts. Non-ocular features show great variation in expression. Children with Stickler syndrome typically have a flat midface with depressed nasal bridge, short nose, anteverted nares, and micrognathia. These features can become less pronounced with age. Midline clefting, if present, ranges in severity from a cleft of the soft palate to Pierre-Robin sequence. There is joint hypermobility which declines with age. Osteoarthritis develops typically in the third or fourth decade. Mild spondyloepiphyseal dysplasia is often apparent radiologically. Sensorineural deafness with high tone loss may be asymptomatic or mild. Occasional findings include slender extremities and long fingers. Stature and intellect are usually normal. Mitral valve prolapse was reported to be a common finding in one series but not in our experience. The majority of families with Stickler syndrome have mutations in the COL2A1 gene and show the characteristic type 1 vitreous phenotype. The remainder with the type 2 vitreous phenotype have mutations in COL11A1 or other loci yet to be identified. Mutations in COL111A2 can give rise to a syndrome with the systemic features of Stickler syndrome but no ophthalmological abnormality.

Clinical and molecular genetics of Stickler syndrome

Stickler syndrome is an autosomal dominant disorder with characteristic ophthalmological and orofacial features, deafness, and arthritis. Abnormalities of vitreous gel architecture are a pathognomonic feature, usually associated with high myopia which is congenital and non-progressive. There is a substantial risk of retinal detachment. Less common ophthalmological features include paravascular pigmented lattice degeneration and cataracts. Non-ocular features show great variation in expression. Children with Stickler syndrome typically have a flat midface with depressed nasal bridge, short nose, anteverted nares, and micrognathia. These features can become less pronounced with age. Midline clefting, if present, ranges in severity from a cleft of the soft palate to Pierre-Robin sequence. There is joint hypermobility which declines with age. Osteoarthritis develops typically in the third or fourth decade. Mild spondyloepiphyseal dysplasia is often apparent radiologically. Sensorineural deafness with high tone loss may be asymptomatic or mild. Occasional findings include slender extremities and long fingers. Stature and intellect are usually normal. Mitral valve prolapse was reported to be a common finding in one series but not in our experience. The majority of families with Stickler syndrome have mutations in the COL2A1 gene and show the characteristic type 1 vitreous phenotype. The remainder with the type 2 vitreous phenotype have mutations in COL11A1 or other loci yet to be identified. Mutations in COL11A2 can give rise to a syndrome with the systemic features of Stickler syndrome but no ophthalmological abnormality.