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]

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]

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]

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]

Cerebral cavernous malformations (CCMs) are vascular malformations in the brain and spinal cord comprising closely clustered, enlarged capillary channels (caverns) with a single layer of endothelium without mature vessel wall elements or normal intervening brain parenchyma. The diameter of CCMs ranges from a few millimeters to several centimeters. CCMs increase or decrease in size and increase in number over time. Hundreds of lesions may be identified, depending on the person's age and the quality and type of brain imaging used. Although CCMs have been reported in infants and children, the majority become evident between the second and fifth decades with findings such as seizures, focal neurologic deficits, nonspecific headaches, and cerebral hemorrhage. Up to 50% of individuals with FCCM remain symptom free throughout their lives. Cutaneous vascular lesions are found in 9% of those with familial cerebral cavernous malformations (FCCM; see Diagnosis/testing) and retinal vascular lesions in almost 5%. [from GeneReviews]

Autosomal recessive primary immunodeficiency-14B (IMD14B) is characterized by onset of recurrent infections in early childhood. Most patients have respiratory infections, but some may develop inflammatory bowel disease or osteomyelitis. Laboratory studies tend to show hypogammaglobulinemia and decreased levels of B cells. Although NK cell and T cell numbers are normal, there may be evidence of impaired immune-mediated cytotoxicity and defective T-cell function (summary by et al., 2018 and et al., 2019). [from OMIM]

Developmental and epileptic encephalopathy-90 (DEE90) is an X-linked neurologic disorder characterized by onset of refractory seizures in the first days or months of life. Although most patients have focal seizures associated with oromotor automatisms and apnea, various seizure types may occur, including epileptic spasms, generalized tonic-clonic, and absence. EEG shows multifocal discharges; hypsarrhythmia, intermittent burst suppression, and slow spike-wave background resembling Lennox-Gastaut syndrome may also be observed. Affected individuals have global developmental delay with variable severity, but it is usually profound or severe. Some are unable to walk or speak, whereas others may achieve some milestones and show autistic features (summary by Fry et al., 2021). For a general phenotypic description and a discussion of genetic heterogeneity of DEE, see 308350. [from OMIM]

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. [from GeneReviews]

Lessel-Kubisch syndrome (LSKB) is characterized by short stature and progeroid features, including prematurely gray hair, pinched facies, and scleroderma-like skin changes. Renal failure-associated hypertension and hypogonadism have also been observed (Lessel et al., 2017). [from OMIM]

GIST-plus syndrome (GISTPS) is an autosomal dominant disorder characterized by incomplete penetrance of multiple mesenchymal tumors of the gastrointestinal tract, including gastrointestinal stromal tumor (GIST), inflammatory fibroid polyps (IFP), and fibroid tumors (FT). Some patients have been reported with coarse facies and skin, broad hands and feet, and premature tooth loss. Isolated GISTs and IFPs are seen in patients with somatic PDGFRA mutations (summary by Manley et al., 2018). [from OMIM]

Bone marrow failure syndrome-5 (BMFS5) is a hematologic disorder characterized by infantile onset of severe red cell anemia requiring transfusion. Additional features include hypogammaglobulinemia, poor growth with microcephaly, developmental delay, and seizures (summary by Toki et al., 2018) For a discussion of genetic heterogeneity of BMFS, see BMFS1 (614675). [from OMIM]

Schimmelpenning-Feuerstein-Mims syndrome, also known as linear sebaceous nevus syndrome, is characterized by sebaceous nevi, often on the face, associated with variable ipsilateral abnormalities of the central nervous system, ocular anomalies, and skeletal defects (summary by Happle, 1991 and Ernst et al., 2007). The linear sebaceous nevi follow the lines of Blaschko (Hornstein and Knickenberg, 1974; Bouwes Bavinck and van de Kamp, 1985). All cases are sporadic. The syndrome is believed to be caused by an autosomal dominant lethal mutation that survives by somatic mosaicism (Gorlin et al., 2001). [from OMIM]

Hyperphosphatemic familial tumoral calcinosis is a rare autosomal recessive metabolic disorder characterized by the progressive deposition of basic calcium phosphate crystals in periarticular spaces, soft tissues, and sometimes bone (Chefetz et al., 2005). The biochemical hallmark of tumoral calcinosis is hyperphosphatemia caused by increased renal absorption of phosphate due to loss-of-function mutations in the FGF23 or GALNT3 (601756) gene. The term 'hyperostosis-hyperphosphatemia syndrome' is sometimes used when the disorder is characterized by involvement of the long bones associated with the radiographic findings of periosteal reaction and cortical hyperostosis. Although some have distinguished HHS from FTC by the presence of bone involvement and the absence of skin involvement (Frishberg et al., 2005), Ichikawa et al. (2010) concluded that the 2 entities represent a continuous spectrum of the same disease, best described as familial hyperphosphatemic tumoral calcinosis. HFTC is considered to be the clinical converse of autosomal dominant hypophosphatemic rickets (ADHR; 193100), an allelic disorder caused by gain-of-function mutations in the FGF23 gene and associated with hypophosphatemia and decreased renal phosphate absorption (Chefetz et al., 2005; Ichikawa et al., 2005). For a general phenotypic description and a discussion of genetic heterogeneity of HFTC, see 211900. [from OMIM]

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. [from GeneReviews]

Primary familial brain calcification (PFBC) is a neurodegenerative disorder with characteristic calcium deposits in the basal ganglia and other brain areas visualized on neuroimaging. Most affected individuals are in good health during childhood and young adulthood and typically present in the fourth to fifth decade with a gradually progressive movement disorder and neuropsychiatric symptoms. The movement disorder first manifests as clumsiness, fatigability, unsteady gait, slow or slurred speech, dysphagia, involuntary movements, or muscle cramping. Neuropsychiatric symptoms, often the first or most prominent manifestations, range from mild difficulty with concentration and memory to changes in personality and/or behavior, to psychosis and dementia. Seizures of various types occur frequently, some individuals experience chronic headache and vertigo; urinary urgency or incontinence may be present. [from GeneReviews]

A rare inherited form of myofibromatosis caused by autosomal dominant mutation(s) in the PDGFRB gene, encoding platelet-derived growth factor receptor beta. The condition is characterized by the onset of solitary or multicentric benign tumors in the skin, striated muscles, bones, and viscera. The lesions may be present at birth or become apparent in early infancy or even occasionally in adult life. [from NCI]

The blepharocheilodontic syndrome is a rare autosomal dominant disorder characterized by lower eyelid ectropion, upper eyelid distichiasis, euryblepharon, bilateral cleft lip and palate, and conical teeth. An additional rare manifestation is imperforate anus (summary by Weaver et al., 2010). [from OMIM]

Developmental and epileptic encephalopathy-47 (DEE47) is a neurologic disorder characterized by onset of intractable seizures in the first days or weeks of life. EEG shows background slowing and multifocal epileptic spikes, and may show hypsarrhythmia. Most patients have developmental regression after seizure onset and show persistent intellectual disability and neurologic impairment, although the severity is variable. Treatment with phenytoin, a voltage-gated sodium channel blocker, may be beneficial (summary by Guella et al., 2016). For a general phenotypic description and a discussion of genetic heterogeneity of DEE, see 308350. [from OMIM]