MedGen

Smith-Lemli-Opitz syndrome (SLOS) is a congenital multiple-anomaly / cognitive impairment syndrome caused by an abnormality in cholesterol metabolism resulting from deficiency of the enzyme 7-dehydrocholesterol (7-DHC) reductase. It is characterized by prenatal and postnatal growth restriction, microcephaly, moderate-to-severe intellectual disability, and multiple major and minor malformations. The malformations include distinctive facial features, cleft palate, cardiac defects, underdeveloped external genitalia in males, postaxial polydactyly, and 2-3 syndactyly of the toes. The clinical spectrum is wide; individuals with normal development and only minor malformations have been described. [from GeneReviews]

Cornelia de Lange syndrome (CdLS) encompasses a spectrum of findings from mild to severe. Severe (classic) CdLS is characterized by distinctive facial features, growth restriction (prenatal onset; <5th centile throughout life), hypertrichosis, and upper-limb reduction defects that range from subtle phalangeal abnormalities to oligodactyly (missing digits). Craniofacial features include synophrys, highly arched and/or thick eyebrows, long eyelashes, short nasal bridge with anteverted nares, small widely spaced teeth, and microcephaly. Individuals with a milder phenotype have less severe growth, cognitive, and limb involvement, but often have facial features consistent with CdLS. Across the CdLS spectrum IQ ranges from below 30 to 102 (mean: 53). Many individuals demonstrate autistic and self-destructive tendencies. Other frequent findings include cardiac septal defects, gastrointestinal dysfunction, hearing loss, myopia, and cryptorchidism or hypoplastic genitalia. [from GeneReviews]

Sialuria is a rare inborn error of metabolism in which excessive free sialic acid is synthesized. Clinical features include hepatosplenomegaly, coarse facial features, and varying degrees of developmental delay (summary by Enns et al., 2001). [from OMIM]

Myhre syndrome is a multisystem progressive connective tissue disorder that often results in significant complications. The highly distinctive (and often severe) findings of joint stiffness, restrictive lung and cardiovascular disease, progressive and proliferative fibrosis, and thickening of the skin usually occur spontaneously. Some proliferation such as abnormal scarring or adhesions may follow trauma, invasive medical procedures, or surgery. Effusions of the heart, airways, lungs, uterus, and peritoneum may occur and can progress to fibrosis. Most affected individuals have characteristic facial features (short palpebral fissures, deeply set eyes, maxillary underdevelopment, short philtrum, thin vermilion of the upper lip, narrow mouth, and prognathism) and developmental delay / cognitive disability, typically in the mild-to-moderate range. Neurobehavioral issues may include autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and/or anxiety. Although immunoglobulin (Ig) G and IgA deficiency are rare, affected individuals can experience recurrent infections (including otitis media, sinusitis, mastoiditis, or croup). Hearing loss can progress over time. Growth may be impaired in early life. Most adolescents develop obesity. Eye findings can include refractive errors, astigmatism, corectopia, and optic nerve anomalies. Gastrointestinal (GI) issues may include gastroesophageal reflux disease, constipation, and encopresis. Less commonly, stenosis of the GI tract, Hirschsprung disease, and/or metabolic dysfunction-associated liver disease may be observed. [from GeneReviews]

Nijmegen breakage syndrome (NBS) is characterized by progressive microcephaly, early growth deficiency that improves with age, recurrent respiratory infections, an increased risk for malignancy (primarily lymphoma), and premature ovarian failure in females. Developmental milestones are attained at the usual time during the first year; however, borderline delays in development and hyperactivity may be observed in early childhood. Intellectual abilities tend to decline over time. Recurrent pneumonia and bronchitis may result in respiratory failure and early death. Other reported malignancies include solid tumors (e.g., medulloblastoma, glioma, rhabdomyosarcoma). [from GeneReviews]

SALL1-related Townes-Brocks syndrome (SALL1-TBS) is characterized by the triad of imperforate anus or anal stenosis, dysplastic ears (overfolded superior helices and preauricular tags; frequently associated with sensorineural and/or conductive hearing impairment), and thumb malformations (duplication of the thumb [preaxial polydactyly], triphalangeal thumbs, and, rarely, hypoplasia of the thumbs) without hypoplasia of the radius. Impaired kidney function, including end-stage kidney disease (ESKD), may occur with or without structural abnormalities (mild malrotation, ectopia, horseshoe kidney, renal hypoplasia, polycystic kidneys, vesicoureteral reflux). Foot malformations (flat feet, overlapping toes) and genitourinary malformations are common. Congenital heart disease occurs in 15% of affected individuals. Developmental delay and/or learning difficulties occur in approximately 15% of affected individuals. Rare features include growth deficiency, Duane anomaly, iris coloboma, and Chiari I malformation. [from GeneReviews]

Jackson-Weiss syndrome (JWS) is an autosomal dominant condition consisting of craniosynostosis characterized by premature fusion of the cranial sutures as well as radiographic anomalies of the feet (summary by Heike et al., 2001). [from OMIM]

Syndromic microphthalmia-2 (MCOPS2) is an X-linked disorder characterized by ocular defects including microphthalmia, microcornea, and congenital cataract; facial dysmorphism including septate nasal cartilage with high nasal bridge; congenital heart defects, most commonly a septal defect; and dental anomalies, most commonly persistent primary teeth and radiculomegaly. Additionally, skeletal defects, mostly hammertoes or 2/3 toe syndactyly, may be present (summary by Hilton et al., 2009). [from OMIM]

MEF2C-related disorder is characterized by moderate-to-profound developmental delay with subsequent intellectual disability, hypotonia, dysmorphic features, seizures, neurobehavioral manifestations (autistic features, sleep issues, stereotypic movements particularly of the hands), vision issues, and cardiac manifestations. Individuals who are able to speak typically only use a few words and are not able to communicate in sentences. Approximately half of individuals are unable to walk independently; however, many are able to walk with some assistance. [from GeneReviews]

Phelan-McDermid syndrome-SHANK3 related (PMS-SHANK3 related) is characterized by neonatal hypotonia, absent to severely delayed speech, developmental delay, and minor dysmorphic facial features. Most affected individuals have moderate-to-profound intellectual disability. Other features include relatively large fleshy hands, dysplastic toenails, and decreased perspiration that results in a tendency to overheat. Normal stature and normal head size distinguish PMS-SHANK3 related from other autosomal chromosome disorders. Neurobehavioral characteristics include mouthing or chewing non-food items, decreased perception of pain, and autism spectrum disorder or autistic-like affect and behavior. Some individuals experience regression / loss of skills, epilepsy, ataxic/abnormal gait, and sleep disturbance (difficulty falling asleep and staying asleep, hypersomnia, and parasomnias). Less commonly, affected individuals may have strabismus, vision problems (hyperopia or myopia), cardiac anomalies, renal anomalies, and lymphedema. Those who have PMS-SHANK3 related due to a ring chromosome 22 also have a high risk of developing features of NF2-related schwannomatosis (NF2). [from GeneReviews]

Bardet-Biedl syndrome-7 (BBS7) is an autosomal recessive disorder characterized by retinitis pigmentosa, postaxial polydactyly, impaired intellectual development, obesity, renal anomalies, and hypogenitalism (Harville et al., 2010). Zaghloul and Katsanis (2009) estimated the contribution of BBS7 gene mutations to the total BBS mutational load to be 1.50%. For a general phenotypic description and a discussion of genetic heterogeneity of Bardet-Biedl syndrome, see BBS1 (209900). [from OMIM]

Hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC), a neurodevelopmental and neurodegenerative disorder, is characterized by severe progressive sensorimotor neuropathy with resulting hypotonia, areflexia, and amyotrophy, and by variable degrees of dysgenesis of the corpus callosum. Mild-to-severe intellectual disability and "psychotic episodes" during adolescence are observed. Sensory modalities are moderately to severely affected beginning in infancy. The average age of onset of walking is 3.8 years; the average age of loss of walking is 13.8 years; the average age of death is 33 years. [from GeneReviews]

Cornelia de Lange syndrome (CdLS) encompasses a spectrum of findings from mild to severe. Severe (classic) CdLS is characterized by distinctive facial features, growth restriction (prenatal onset; <5th centile throughout life), hypertrichosis, and upper-limb reduction defects that range from subtle phalangeal abnormalities to oligodactyly (missing digits). Craniofacial features include synophrys, highly arched and/or thick eyebrows, long eyelashes, short nasal bridge with anteverted nares, small widely spaced teeth, and microcephaly. Individuals with a milder phenotype have less severe growth, cognitive, and limb involvement, but often have facial features consistent with CdLS. Across the CdLS spectrum IQ ranges from below 30 to 102 (mean: 53). Many individuals demonstrate autistic and self-destructive tendencies. Other frequent findings include cardiac septal defects, gastrointestinal dysfunction, hearing loss, myopia, and cryptorchidism or hypoplastic genitalia. [from GeneReviews]

Cornelia de Lange syndrome (CdLS) encompasses a spectrum of findings from mild to severe. Severe (classic) CdLS is characterized by distinctive facial features, growth restriction (prenatal onset; <5th centile throughout life), hypertrichosis, and upper-limb reduction defects that range from subtle phalangeal abnormalities to oligodactyly (missing digits). Craniofacial features include synophrys, highly arched and/or thick eyebrows, long eyelashes, short nasal bridge with anteverted nares, small widely spaced teeth, and microcephaly. Individuals with a milder phenotype have less severe growth, cognitive, and limb involvement, but often have facial features consistent with CdLS. Across the CdLS spectrum IQ ranges from below 30 to 102 (mean: 53). Many individuals demonstrate autistic and self-destructive tendencies. Other frequent findings include cardiac septal defects, gastrointestinal dysfunction, hearing loss, myopia, and cryptorchidism or hypoplastic genitalia. [from GeneReviews]

Wiedemann-Steiner syndrome (WSS) is characterized by developmental delay, intellectual disability, and characteristic facial features, with or without additional congenital anomalies. The facial features include thick eyebrows with lateral flare, vertically narrow and downslanted palpebral fissures, widely spaced eyes, long eyelashes, wide nasal bridge, broad nasal tip, thin vermilion of the upper lip, and thick scalp hair. About 60% of affected individuals have hypertrichosis cubiti ("hairy elbows"), which was once thought to be pathognomic for the syndrome, with a majority having hypertrichosis of other body parts. Other clinical features include feeding difficulties, prenatal and postnatal growth restriction, epilepsy, ophthalmologic anomalies, congenital heart defects, hand anomalies (such as brachydactyly and clinodactyly), hypotonia, vertebral anomalies (especially fusion anomalies of the cervical spine), renal and uterine anomalies, immune dysfunction, brain malformations, and dental anomalies. [from GeneReviews]

Cranioectodermal dysplasia (CED) is a ciliopathy with skeletal involvement (narrow thorax, shortened proximal limbs, syndactyly, polydactyly, brachydactyly), ectodermal features (widely spaced hypoplastic teeth, hypodontia, sparse hair, skin laxity, abnormal nails), joint laxity, growth deficiency, and characteristic facial features (frontal bossing, low-set simple ears, high forehead, telecanthus, epicanthal folds, full cheeks, everted lower lip). Most affected children develop nephronophthisis that often leads to end-stage kidney disease in infancy or childhood, a major cause of morbidity and mortality. Hepatic fibrosis and retinal dystrophy are also observed. Dolichocephaly, often secondary to sagittal craniosynostosis, is a primary manifestation that distinguishes CED from most other ciliopathies. Brain malformations and developmental delay may also occur. [from GeneReviews]

The TP63-related disorders comprise six overlapping phenotypes: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome (which includes Rapp-Hodgkin syndrome). Acro-dermo-ungual-lacrimal-tooth (ADULT) syndrome. Ectrodactyly, ectodermal dysplasia, cleft lip/palate syndrome 3 (EEC3). Limb-mammary syndrome. Split-hand/foot malformation type 4 (SHFM4). Isolated cleft lip/cleft palate (orofacial cleft 8). Individuals typically have varying combinations of ectodermal dysplasia (hypohidrosis, nail dysplasia, sparse hair, tooth abnormalities), cleft lip/palate, split-hand/foot malformation/syndactyly, lacrimal duct obstruction, hypopigmentation, hypoplastic breasts and/or nipples, and hypospadias. Findings associated with a single phenotype include ankyloblepharon filiforme adnatum (tissue strands that completely or partially fuse the upper and lower eyelids), skin erosions especially on the scalp associated with areas of scarring, and alopecia, trismus, and excessive freckling. [from GeneReviews]

Feingold syndrome 1 (referred to as FS1 in this GeneReview) is characterized by digital anomalies (shortening of the 2nd and 5th middle phalanx of the hand, clinodactyly of the 5th finger, syndactyly of toes 2-3 and/or 4-5, thumb hypoplasia), microcephaly, facial dysmorphism (short palpebral fissures and micrognathia), gastrointestinal atresias (primarily esophageal and/or duodenal), and mild-to-moderate learning disability. [from GeneReviews]

Multiple synostoses syndrome is characterized by multiple joint fusions, usually commencing in the hands, conductive deafness, and characteristic facial features, including a broad, tubular-shaped nose and a thin upper vermilion. Other features include brachydactyly, hypoplastic or absent middle phalanges, radial head dislocation, and pectus carinatum (summary by Takahashi et al., 2001). Genetic Heterogeneity of Multiple Synostoses Syndrome Other forms of multiple synostoses syndrome include SYNS2 (610017), caused by mutation in the GDF5 gene (601146) on chromosome 20q11; SYNS3 (612961), caused by mutation in the FGF9 gene (600921) on chromosome 13q12; and SYNS4 (617898), caused by mutation in the GDF6 gene (601147) on chromosome 8q22. [from OMIM]

Brachydactyly type A2 is an autosomal dominant disorder characterized by malformations of the middle phalanx of the index finger and by anomalies of the second toe (summary by Su et al., 2011). [from OMIM]