Harderoporphyria (HARPO) is a rare erythropoietic variant form of hereditary coproporphyria (HCP; 121300) characterized by neonatal hemolytic anemia, sometimes accompanied by skin lesions, and massive excretion of harderoporphyrin in feces. During childhood and adulthood, a mild residual anemia is chronically observed (review by Schmitt et al., 2005).

Several documented cases of glutathione peroxidase (GPX1; 138320) deficiency in association with hemolytic anemia have been reported. However, Paglia (1989) stated: 'To date, no defects in glutathione peroxidase have been unequivocally incriminated in the pathogenesis of hemolytic syndromes, although several instances of partial deficiency have been reported in patients with anemias of unknown etiology. This association may be coincidental, since there is a broad range of ethnic variation in the erythrocyte enzyme' (Beutler and Matsumoto, 1975).

A rare genetic lethal multiple congenital anomalies/dysmorphic syndrome characterized by consistently abnormal facial appearance, true or apparent hydrocephalus, motor and cognitive developmental delay, failure to thrive (feeding difficulties, vomiting, chest infections) and death within a few months of birth. Carp mouth, hairiness of the forehead, neonatal hyperbilirubinemia and advanced bone age may also be associated. There have been no further descriptions in the literature since 1991.

Any hereditary elliptocytosis in which the cause of the disease is a mutation in the SPTA1 gene.

A complex form of hereditary spastic paraplegia characterised by a spastic paraplegia presenting in adolescence, associated with the additional manifestations of sensorial hearing impairment due to auditory neuropathy and persistent vomiting due to a hiatal or paraoesophageal hernia. The phenotype has been mapped to a locus on chromosome 1p31.1-p21.1.

Congenital disorder of glycosylation type IIm, or developmental and epileptic encephalopathy-22 (DEE22), is an X-linked dominant severe neurologic disorder characterized by infantile-onset seizures, hypsarrhythmia on EEG, hypotonia, and developmental delay associated with severe intellectual disability and lack of speech. These features are consistent with developmental and epileptic encephalopathy (DEE). Brain malformations usually include cerebral and cerebellar atrophy. Additionally, some patients may have dysmorphic features or coarse facies (Ng et al., 2013; Kodera et al., 2013). For a general discussion of CDGs, see CDG1A (212065) and CDG2A (212066). For a general phenotypic description and a discussion of genetic heterogeneity of DEE, see 308350.