MedGen

Spinocerebellar ataxia-27A (SCA27A) is an autosomal dominant neurologic disorder characterized by general cerebellar dysfunction manifest as gait disturbances, ataxia, tremor, dysarthria, and gaze-evoked nystagmus. The age at onset is highly variable: some patients present in infancy with nystagmus or delayed motor development, whereas others present as adults with tremor or gait difficulties. The disorder is slowly progressive, and ataxia may be very subtle or even absent. Cerebellar atrophy may or may not be observed on brain imaging. Individuals with SCA27A often show mild developmental delay with variably impaired intellectual development. Many patients report an exacerbation of symptoms with fever, emotional stress, or exercise, which can be reminiscent of episodic ataxia or be associated with outbursts, depression, or other behavioral and psychiatric disturbances. There is significant inter- and intrafamilial variability and patients show various combinations of neurologic features (summary by Tucker et al., 2013; Piarroux et al., 2020; Ceroni et al., 2023). For a general discussion of autosomal dominant spinocerebellar ataxia, see SCA1 (164400). [from OMIM]

Benign familial hematuria (BFH) is an autosomal dominant condition manifest as nonprogressive isolated microscopic hematuria that does not result in renal failure. It is characterized pathologically by thinning of the glomerular basement membrane (GBM), and can be considered the mildest end of the spectrum of renal diseases due to type IV collagen defects of the basement membrane. The most severe end of the spectrum is represented by Alport syndrome (see 301050), which results in end-stage renal failure and may be associated with hearing loss and ocular anomalies (review by Lemmink et al. (1996)). For a discussion of genetic heterogeneity of BFH, see BFH1 (141200). [from OMIM]

PPP2R5D-related neurodevelopmental disorder is characterized by mild to severe neurodevelopmental delay. Pronounced hypotonia with delay in gross motor skills is common. Onset of independent walking varies widely and ataxia is reported. All reported individuals have speech impairment, with a wide range of abilities. Autism spectrum disorder is reported in six individuals. Macrocephaly is common. Seizures and ophthalmologic abnormalities are reported in fewer than half of individuals. Additional anomalies include skeletal, endocrine, and cardiac malformations, each reported in a few individuals. To date, 23 individuals with PPP2R5D-related neurodevelopmental disorder have been reported. [from GeneReviews]

Lacrimoauriculodentodigital syndrome-1 (LADD1) is a multiple congenital anomaly disorder mainly affecting lacrimal glands and ducts, salivary glands and ducts, ears, teeth, and distal limb segments (summary by Rohmann et al., 2006). Genetic Heterogeneity of Lacrimoauriculodentodigital Syndrome LADD syndrome-2 (LADD2; 620192) is caused by mutation in the FGFR3 gene (134934) on chromosome 4p16, and LADD syndrome-3 (LADD3; 620193) is caused by mutation in the FGF10 gene, an FGFR ligand, on chromosome 5p12. [from OMIM]

Lacrimoauriculodentodigital syndrome-3 (LADD3) is a multiple congenital anomaly disorder characterized by aplasia, atresia or hypoplasia of the lacrimal and salivary systems, cup-shaped ears, hearing loss, and dental and digital anomalies (summary by Milunsky et al., 2006). [from OMIM]

Lacrimoauriculodentodigital syndrome-2 (LADD2) is a multiple congenital anomaly disorder mainly affecting lacrimal glands and ducts, salivary glands and ducts, ears, teeth, and distal limb segments (summary by Rohmann et al., 2006). [from OMIM]

Late-onset spinocerebellar ataxia-27B (SCA27B) is an autosomal dominant neurodegenerative disorder characterized by the onset of gait and appendicular ataxia in adulthood, usually around age 55 (range 30 to late eighties). About half of patients present with episodic features. The disorder is slowly progressive, and some patients may lose independent ambulation. Additional features include downbeat and horizontal nystagmus, diplopia, vertigo, and dysarthria. Brain imaging tends to show cerebellar atrophy (Pellerin et al., 2023). For a general discussion of autosomal dominant spinocerebellar ataxia, see SCA1 (164400). [from OMIM]

Bent bone dysplasia syndrome-2 (BBDS2) is characterized by defects in both the axial and appendicular skeleton, with radiographic findings of undermineralized bone and a distinct angulation of the mid femoral shaft. Extraskeletal features include facial dysmorphisms, abnormally formed ears with tags, widely spaced nipples, and atrial septal defects. Abnormalities of muscle function are suggested by the presence of elbow fusions, ulnar flexion contractions at the wrist, and bilateral talipes equinovarus, as well as failure to mount a respiratory effort at birth (Barad et al., 2020). For a general phenotypic description and discussion of genetic heterogeneity of bent bone dysplasia syndrome, see BBDS1 (614592). [from OMIM]

Nephrotic syndrome type 26 (NPHS26) is an autosomal recessive renal disorder characterized by onset of proteinuria in the first months or years of life. Other features may include edema and hypoalbuminemia. Renal biopsy shows focal segmental glomerulosclerosis (FSGS), diffuse mesangial sclerosis (DMS), abnormalities of the glomerular basement membrane, and effacement of podocyte foot processes. There is variability in disease progression and response to treatment: some patients respond to steroids, whereas others show steroid resistance and progression to end-stage renal disease (ESRD) (Braun et al., 2019; Taniguchi et al., 2021). For a general phenotypic description and a discussion of genetic heterogeneity of nephrotic syndrome, see NPHS1 (256300). [from OMIM]

Stickler syndrome type VI (STL6) is characterized by early-onset progressive hearing loss and progressive myopia, with variable manifestation of facial dysmorphism and skeletal anomalies (Nixon et al., 2019; Rad et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of Stickler syndrome, see STL1 (108300). [from OMIM]

Distal arthrogryposis type 11 (DA11) is an autosomal dominant disorder characterized mainly by camptodactyly. Other features include absent flexion creases and limited forearm supination (Zhou et al., 2019). [from OMIM]

X-linked intellectual developmental disorder-110 (XLID110) is characterized by moderately to severely impaired intellectual development. [from OMIM]

Von Willebrand disease (VWD), a congenital bleeding disorder caused by deficient or defective plasma von Willebrand factor (VWF), may only become apparent on hemostatic challenge, and bleeding history may become more apparent with increasing age. Recent guidelines on VWD have recommended taking a VWF level of 30 or 40 IU/dL as a cutoff for those diagnosed with the disorder. Individuals with VWF levels greater than 30 IU/dL and lower than 50 IU/dL can be described as having a risk factor for bleeding. This change in guidelines significantly alters the proportion of individuals with each disease type. Type 1 VWD (~30% of VWD) typically manifests as mild mucocutaneous bleeding. Type 2 VWD accounts for approximately 60% of VWD. Type 2 subtypes include: Type 2A, which usually manifests as mild-to-moderate mucocutaneous bleeding; Type 2B, which typically manifests as mild-to-moderate mucocutaneous bleeding that can include thrombocytopenia that worsens in certain circumstances; Type 2M, which typically manifests as mild-moderate mucocutaneous bleeding; Type 2N, which can manifest as excessive bleeding with surgery and mimics mild hemophilia A. Type 3 VWD (<10% of VWD) manifests with severe mucocutaneous and musculoskeletal bleeding. [from GeneReviews]

Intermediate junctional epidermolysis bullosa 3A (JEB3A) is an autosomal recessive blistering disease of skin and mucous membranes. Blistering is less severe than in severe JEB (see 226700). The plane of skin cleavage is through the lamina lucida of the cutaneous basement membrane zone. Nail and dental abnormalities occur. Blistering does not affect the life span of affected individuals (summary by Has et al., 2020). For a discussion of genetic heterogeneity of the subtypes of JEB, see JEB1A (226650). Reviews Has et al. (2020) reviewed the clinical and genetic aspects, genotype-phenotype correlations, disease-modifying factors, and natural history of epidermolysis bullosa. [from OMIM]

Intermediate junctional epidermolysis bullosa 5A (JEB5A) is an autosomal recessive blistering disease of skin and mucous membranes. Blistering is less severe than in severe JEB (see 226700). The plane of skin cleavage is through the lamina lucida of the cutaneous basement membrane zone. Nails may be dystrophic and dental enamel defects are present. Blistering does not affect the life span of affected individuals (summary by Has et al., 2020). For a discussion of genetic heterogeneity of the subtypes of JEB, see JEB1A (226650). Reviews Has et al. (2020) reviewed the clinical and genetic aspects, genotype-phenotype correlations, disease-modifying factors, and natural history of epidermolysis bullosa. [from OMIM]

X-linked systemic autoinflammatory disease (SAIDX) is characterized by the onset of systemic autoinflammation in the first months of life. Features include lymphadenopathy, hepatosplenomegaly, fever, panniculitis, and nodular skin rash. Additional manifestations may include inflammation of the optic nerve, intracranial hemorrhage, and lipodystrophy. Laboratory studies show hypogammaglobulinemia, increased or decreased white blood cell count, autoimmune cytopenias, elevated serum inflammatory markers, and a type I interferon signature (de Jesus et al., 2020 and Lee et al., 2022). [from OMIM]

Epidermolysis bullosa with pyloric atresia (EB-PA) is characterized by fragility of the skin and mucous membranes, manifested by blistering with little or no trauma; congenital pyloric atresia; and ureteral and renal anomalies (dysplastic/multicystic kidney, hydronephrosis/hydroureter, ureterocele, duplicated renal collecting system, absent bladder). The course of EB-PA is usually severe and often lethal in the neonatal period. Most affected children succumb as neonates; those who survive may have severe blistering with formation of granulation tissue on the skin around the mouth, nose, fingers, and toes, and internally around the trachea. However, some affected individuals have little or no blistering later in life. Additional features shared by EB-PA and the other major forms of EB include congenital localized absence of skin (aplasia cutis congenita) affecting the extremities and/or head, milia, nail dystrophy, scarring alopecia, hypotrichosis, contractures, and dilated cardiomyopathy. [from GeneReviews]

Waardenburg syndrome type 2F (WS2F) is characterized by congenital or neonatal-onset sensorineural hearing loss and altered pigmentation of the iris, hair, and skin. Variable expressivity has been reported, even among patients with the same mutation (Ogawa et al., 2017; Vona et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of WS2, as well as a brief description of other clinical variants of Waardenburg syndrome (WS1, 193500; WS3, 148820; and WS4, 277580), see WS2A (193510). [from OMIM]

Severe junctional epidermolysis bullosa 3B (JEB3B) is an autosomal recessive skin blistering disorder characterized by extreme fragility of the skin and epithelia of various extracutaneous tissues. Skin blisters and erosions are present at birth. The plane of skin cleavage is through the lamina lucida of the cutaneous basement membrane zone. Patients die in infancy to early adulthood (summary by Has et al., 2020). For a discussion of genetic heterogeneity of the subtypes of JEB, see JEB1A (226650). Reviews Has et al. (2020) reviewed the clinical and genetic aspects, genotype-phenotype correlations, disease-modifying factors, and natural history of epidermolysis bullosa. [from OMIM]