MedGen

Congenital disorders of glycosylation (CDGs) are metabolic deficiencies in glycoprotein biosynthesis that usually cause severe mental and psychomotor retardation. Different forms of CDGs can be recognized by altered isoelectric focusing (IEF) patterns of serum transferrin. For a general discussion of CDGs, see CDG Ia (212065) and CDG Ib (602579). [from OMIM]

Congenital myasthenic syndrome associated with AChR deficiency is a disorder of the postsynaptic neuromuscular junction (NMJ) clinically characterized by early-onset muscle weakness with variable severity. Electrophysiologic studies show low amplitude of the miniature endplate potential (MEPP) and current (MEPC) resulting from deficiency of AChR at the endplate. Treatment with cholinesterase inhibitors or amifampridine may be helpful (summary by Engel et al., 2015). For a discussion of genetic heterogeneity of CMS, see CMS1A (601462). [from OMIM]

DNMT1-related disorder is a degenerative disorder of the central and peripheral nervous systems comprising a phenotypic spectrum that includes hereditary sensory and autonomic neuropathy type 1E (HSAN1E) and autosomal dominant cerebellar ataxia, deafness, and narcolepsy (ADCA-DN). DNMT1 disorder is often characterized by moderate-to-severe sensorineural hearing loss beginning in the teens or early 20s, sensory impairment, sudomotor dysfunction (loss of sweating), and dementia usually beginning in the mid-40s. In some affected individuals, narcolepsy/cataplexy syndrome and ataxia are predominant findings. [from GeneReviews]

Usher syndrome type I (USH1) is characterized by congenital, bilateral, profound sensorineural hearing loss, vestibular areflexia, and adolescent-onset retinitis pigmentosa (RP). Unless fitted with a cochlear implant, individuals do not typically develop speech. RP, a progressive, bilateral, symmetric degeneration of rod and cone functions of the retina, develops in adolescence, resulting in progressively constricted visual fields and impaired visual acuity. [from GeneReviews]

A rare neurologic disease characterized by an excessive daytime sleepiness with long and unrefreshing naps, and/or prolonged and undisturbed nocturnal sleep, impaired daytime alertness, and/or sleep inertia (ie, great difficulty in waking up after sleep) and where other causes have been excluded. [from ORDO]

Soft and hard-palate submucous clefts are characterized by bony defects in the midline of the soft and hard palate that are covered by the lining (ie mucous membrane) of the roof of the mouth. [from HPO]

Amelogenesis imperfecta is an inherited defect of dental enamel formation that shows both clinical and genetic heterogeneity. In the hypoplastic type of AI, the enamel is of normal hardness but does not develop to normal thickness. The thinness of the enamel makes the teeth appear small. Radiographically, enamel contrasts normally from dentin. The surface of the enamel can vary, showing smooth, rough, pitted, or local forms (Witkop, 1988). [from OMIM]

An amelogenesis imperfecta associated with mutation in a gene in the Xq22-q28 region. [from MONDO]

A rare bacterial infectious disease characterized by infection of a native or prosthetic heart valve, the endocardial surface, or an indwelling cardiac device. Main causative agents are Gram-positive bacteria, most commonly <i>Staphylococcus</i> and <i>Streptococcus</i> species. Signs and symptoms include high fever or prolonged subfebrile state, excessive sweating, malaise, asthenia, arthralgia, myalgia, weight loss, headache, nausea, dyspnea, cough, heart murmurs, and petechiae of the skin. The most common complications are embolism in different organs and ischemic stroke, sepsis, heart failure, and renal failure. [from ORDO]