MedGen

AP-4-associated hereditary spastic paraplegia (HSP), also known as AP-4 deficiency syndrome, is a group of neurodegenerative disorders characterized by a progressive, complex spastic paraplegia with onset typically in infancy or early childhood. Early-onset hypotonia evolves into progressive lower-extremity spasticity. The majority of children become nonambulatory and usually wheelchair bound. Over time spasticity progresses to involve the upper extremities, resulting in a spastic tetraplegia. Associated complications include dysphagia, contractures, foot deformities, dysregulation of bladder and bowel function, and a pseudobulbar affect. About 50% of affected individuals have seizures. Postnatal microcephaly (usually in the -2SD to -3SD range) is common. All have developmental delay. Speech development is significantly impaired and many affected individuals remain nonverbal. Intellectual disability in older children is usually moderate to severe. [from GeneReviews]

Any autosomal dominant nonsyndromic deafness in which the cause of the disease is a mutation in the CRYM gene. [from MONDO]

Oocyte/zygote/embryo maturation arrest-19 (OZEMA19) is characterized by female infertility due to oocyte maturation arrest and early embryonic arrest. Oocyte arrest at the germinal vesicle stage has been observed. In other patients, most oocytes can be fertilized and begin cleavage, but they undergo maturation arrest at the 2- to 7-cell stage on day 3 (Mu et al., 2019; Huang et al., 2022). For a discussion of genetic heterogeneity of OZEMA, see 615774. [from OMIM]

Oocyte/zygote/embryo maturation arrest-18 (OZEMA18) is characterized by female infertility due to early embryonic arrest. Most oocytes can be fertilized and begin cleavage, but very few viable embryos are obtained and most fail to establish pregnancy (Mu et al., 2019). For a discussion of genetic heterogeneity of OZEMA, see 615774. [from OMIM]

A lasting absence of total IgG and total IgA and total IgM in the blood circulation, whereby at most trace quantities can be measured. [from HPO]

A type of HCD characterized by the production of incomplete monoclonal mu-heavy chains without associated light chains. The clinical presentation resembles that of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). [from ORDO]