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]

Immunodeficiency-112 (IMD112) is an autosomal recessive primary immunologic disorder with variable manifestations beginning in early childhood. Some patients have recurrent bacterial, viral, and fungal infections, including disseminated bacillus Calmette-Guerin (BCG)-related infections, whereas at least 1 patient only presented with BCG-related infections. Immunologic workup shows variable abnormalities affecting lymphoid immunity, including hypogammaglobulinemia, lymphopenia or paradoxical lymphocytosis, and defects in B, T, and NK cell differentiation and function mainly due to disruption of the noncanonical NFKB (see 164011) signaling pathway (Willmann et al., 2014; Schlechter et al., 2017). [from OMIM]

Oocyte/zygote/embryo maturation arrest-20 (OZEMA20) is characterized by early embryonic arrest with fragmentation. Extrusion of a large polar body 1 is observed in some patients (Zhang et al., 2021; Zhang et al., 2022). For a discussion of genetic heterogeneity of OZEMA, see 615774. [from OMIM]

Congenital myopathy-18 (CMYP18) is a disorder of the skeletal muscle characterized by the onset of symptoms of muscle weakness in early childhood, including in utero and infancy. There is clinical heterogeneity in the manifestations and severity, ranging from fetal akinesia sequence causing early death to onset of symptoms in adulthood. Most affected individuals show delayed motor development with generalized hypotonia and progressive axial and limb muscle weakness beginning soon after birth or in infancy. Additional features may include swallowing difficulties, external ophthalmoplegia, ptosis, high-arched palate, and respiratory insufficiency, which can lead to death in severe cases. Muscle biopsy shows variable morphologic abnormalities, including alveolar changes in the intermyofibrillar network, fiber size variability, focal disorganization, internal nuclei, and dilated sarcoplasmic reticulum and T-tubules. The disorder results from a defect in excitation-contraction coupling in skeletal muscle (Schartner et al., 2017; Ravenscroft et al., 2021; Mauri et al., 2021; Yis et al., 2019). For a discussion of genetic heterogeneity of congenital myopathy, see CMYP1A (117000). [from OMIM]

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]

Developmental and epileptic encephalopathy-110 (DEE110) is an autosomal recessive disorder characterized by profound global developmental delay and hypotonia apparent in infancy followed by onset of seizures in the first months or years of life. Affected individuals achieve almost no developmental milestones and show impaired intellectual development, poor or absent speech, inability to walk or grasp objects, peripheral spasticity, and poor eye contact. Brain imaging shows hypoplastic corpus callosum and cortical atrophy (Dahimene et al., 2022). For a discussion of genetic heterogeneity of DEE, see 308350. [from OMIM]

Neurodevelopmental disorder with speech impairment and with or without seizures (NEDSIS) is a phenotypically heterogeneous neurologic disorder whose severity appears to depend on the functional effect of the CACNA1I mutation. Severely affected individuals present in infancy with profound global developmental delay, hypotonia, delayed or absent walking, absent speech, feeding difficulties, cortical visual impairment, and onset of hyperexcitability and seizures in the first months or years of life. They achieve little or no developmental progress and may be tube-fed. Mutations in these individuals occurred de novo. In contrast, a milder phenotype associated with an inherited mutation has been found in a family with mild to moderate cognitive impairment and mild speech delay, usually without seizures (El Ghaleb et al., 2021). [from OMIM]

Neurodevelopmental disorder with hypotonia, language delay, and skeletal defects with or without seizures (NEDHLSS) is characterized by global developmental delay apparent from infancy. Affected individuals show severe hypotonia with delayed walking or inability to walk, poor or absent speech, and impaired intellectual development with behavioral abnormalities. Most patients have early-onset seizures, mild skeletal defects that are usually distal, and nonspecific dysmorphic features. More severely affected individuals have additional congenital abnormalities; however, cardiac involvement is rare (summary by Rodan et al., 2021). [from OMIM]

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

Neurocardiofaciodigital syndrome (NCFD) is characterized by severe developmental delay, variable brain anomalies, congenital heart defects, dysmorphic facial features, and a distinctive type of synpolydactyly with a supernumerary hypoplastic digit between the fourth and fifth digits of the hands and/or feet. Other features include eye abnormalities, hearing impairment, and electroencephalogram anomalies (summary by Horn et al., 2021). [from OMIM]

Recurrent gastrointestinal ulceration with dysfunctional platelets (GURDP) is an autosomal recessive disorder characterized by onset of severe gastrointestinal mucosal ulceration in early childhood. Affected individuals may have secondary iron deficiency anemia or malnourishment. Studies of platelet aggregation show a functional defect associated with decreased thromboxane-A2 production and decreased eicosanoid biosynthesis. The gastrointestinal disease is believed to result from decreased or absent production of prostaglandins that protect the gut mucosa (summary by Adler et al., 2008 and Faioni et al., 2014). [from OMIM]

Split-foot malformation with mesoaxial polydactyly (SFMMP) is characterized by a split-foot defect and nail abnormalities of the hands, as well as hearing loss in some patients (Spielmann et al., 2016). [from OMIM]

Developmental delay with or without intellectual impairment or behavioral abnormalities (DDIB) is an autosomal dominant disorder with a nonspecific phenotype of developmental delay. Additional features may include neonatal feeding problems, hypotonia, and dysmorphic facial features (Dulovic-Mahlow et al., 2019; van Woerden et al., 2021). [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]

Bartsocas-Papas syndrome-2 (BPS2) is a severe form of popliteal pterygium disorder characterized by cutaneous webbing across one or more joints, cleft lip and/or palate, syndactyly, and genital malformations (summary by Leslie et al., 2015). [from OMIM]