Previously apparently undescribed syndrome: shallow orbits, ptosis, coloboma, trigonocephaly, gyral malformations, and mental and growth retardation

The Clinical Manifestations and Genetic Implications of Baraitser-Winter Syndrome Type 2

An 18-year-old Caucasian male was born by cesarean section weighing 2.6 kg (5 lb 14 oz) at birth after an uncomplicated pregnancy with no perinatal complications. Around 4 to 5 months of age, the patient's mother initially became concerned as he was experiencing signs of developmental delay and a mild floppy tone, in addition to facial features that resembled some form of mental retardation. The patient's older brother also experienced similar developmental symptoms and facial features that presented around the same age period as our patient. It was initially thought to be Down syndrome; however, both the patient and his brother tested negative for Down syndrome on chromosomal analyses. There was also a question of whether the patient had some form of autism spectrum disorder, but doctors were unable to specifically confirm this. Now at the age of 18 years, the patient has no understandable speech with distinctive facial features such as a broad nasal bridge and prominent epicanthic folds, lissencephaly, smaller than average head size, intellectual disability, and hearing loss. It was discovered, through trio-based exome sequencing, that the patient had a de novo missense mutation (p.Ser155Phe) in the ACTG1 gene, which has been linked to the rare syndrome known as Baraister-Winter syndrome type 2. Baraitser-Winter syndrome 2 is a unique variant that is clinically similar to Baraitser-Winter syndrome type 1; however, only seven previous cases have been reported.

Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases

Baraitser-Winter, Fryns-Aftimos and cerebrofrontofacial syndrome types 1 and 3 have recently been associated with heterozygous gain-of-function mutations in one of the two ubiquitous cytoplasmic actin-encoding genes ACTB and ACTG1 that encode β- and γ-actins. We present detailed phenotypic descriptions and neuroimaging on 36 patients analyzed by our group and six cases from the literature with a molecularly proven actinopathy (9 ACTG1 and 33 ACTB). The major clinical anomalies are striking dysmorphic facial features with hypertelorism, broad nose with large tip and prominent root, congenital non-myopathic ptosis, ridged metopic suture and arched eyebrows. Iris or retinal coloboma is present in many cases, as is sensorineural deafness. Cleft lip and palate, hallux duplex, congenital heart defects and renal tract anomalies are seen in some cases. Microcephaly may develop with time. Nearly all patients with ACTG1 mutations, and around 60% of those with ACTB mutations have some degree of pachygyria with anteroposterior severity gradient, rarely lissencephaly or neuronal heterotopia. Reduction of shoulder girdle muscle bulk and progressive joint stiffness is common. Early muscular involvement, occasionally with congenital arthrogryposis, may be present. Progressive, severe dystonia was seen in one family. Intellectual disability and epilepsy are variable in severity and largely correlate with CNS anomalies. One patient developed acute lymphocytic leukemia, and another a cutaneous lymphoma, indicating that actinopathies may be cancer-predisposing disorders. Considering the multifaceted role of actins in cell physiology, we hypothesize that some clinical manifestations may be partially mutation specific. Baraitser-Winter cerebrofrontofacial syndrome is our suggested designation for this clinical entity.

Cerebro-fronto-facial syndrome type 3 with polymicrogyria: a clinical presentation of Baraitser-Winter syndrome

Baraitser-Winter syndrome (BRWS) is a rare condition affecting the development of the brain and the face. The most common characteristics are unusual facial appearance including hypertelorism and ptosis, ocular colobomas, hearing loss, impaired neuronal migration and intellectual disability. BRWS is caused by mutations in the ACTB and ACTG1 genes. Cerebro-fronto-facial syndrome (CFFS) is a clinically heterogeneous condition with distinct facial dysmorphism, and brain abnormalities. Three subtypes are identified. We report a female infant with striking facial features and brain anomalies (included polymicrogyria) that fit into the spectrum of the CFFS type 3 (CFFS3). She also had minor anomalies on her hands and feet, heart and kidney malformations, and recurrent infections. DNA investigations revealed c.586C>T mutation (p.Arg196Cys) in ACTB. This mutation places this patient in the spectrum of BRWS. The same mutation has been detected in a polymicrogyric patient reported previously in literature. We expand the malformation spectrum of BRWS/CFFS3, and present preliminary findings for phenotype-genotype correlation in this spectrum.

Short stature, sensorineural deafness, ocular abnormalities and severe mental retardation in two siblings. A new syndrome?

We describe a brother and sister with craniofacial dysmorphism, short stature, relative obesity, sensorineural deafness, multiple pigmented naevi and severe mental retardation. One sibling had keratoconus and the other had an iris coloboma. Dysmorphic features included brachycephaly, hypotelorism, small mouth, thin lips, pterygium colli, broad chest, widely spaced nipples and cutaneous second and third toe syndactyly. The children demonstrate some features of Noonan syndrome, but we believe that they have a different and distinctive phenotype. We have reviewed similar cases in the literature and discuss these in the context of our cases, who may have a previously undescribed syndrome.