X-linked Dandy-Walker malformation with intellectual disability, basal ganglia disease and seizures (XDIBS), or Pettigrew syndrome is a central nervous system malformation characterized by severe intellectual deficit, early hypotonia with progression to spasticity and contractures, choreoathetosis, seizures, dysmorphic face (long face with prominent forehead), and brain imaging abnormalities such as Dandy-Walker malformation, and iron deposition. (From Mondo:0010574)

Mulvihill-Smith syndrome is characterized by premature aging, multiple pigmented nevi, lack of facial subcutaneous fat, microcephaly, short stature, sensorineural hearing loss, and mental retardation. Immunodeficiency may also be a feature. Adult manifestations include the development of tumors, a sleep disorder with severe insomnia, and cognitive decline (summary by Yagihashi et al., 2009).

Autosomal dominant deafness-7 (DFNA7) is a form of progressive sensorineural hearing loss with highly variable age at onset and severity, even within families. The age at onset ranges from congenital to mid-adulthood. Some patients may have associated vertigo (summary by Wesdorp et al., 2018).

X-linked deafness-4 is a nonsyndromic form of progressive hearing loss with postlingual onset. Affected males show earlier onset of hearing loss than affected females (summary by del Castillo et al., 1996).

Any autosomal dominant nonsyndromic deafness in which the cause of the disease is a mutation in the MYH9 gene.

Any autosomal dominant nonsyndromic deafness in which the cause of the disease is a mutation in the GJB3 gene.

X-linked retinitis pigmentosa and sinorespiratory infections with or without deafness (RPSRDF) is characterized by typical features of RP, including night blindness, constricted visual fields, progressive reduction in visual acuity, bone-spicule pigmentation, and extinguished responses on electroretinography. Affected individuals also experience severe recurrent sinorespiratory infections, and some develop progressive hearing loss. Carrier females may show an attenuated ocular and/or respiratory phenotype (Zito et al., 2003; Moore et al., 2006).

Combined oxidative phosphorylation deficiency-55 (COXPD55) is characterized by global developmental delay, hypotonia, short stature, and impaired intellectual development with speech disabilities in childhood. Indolent progressive external ophthalmoplegia phenotype has been described in 1 patient (summary by Olahova et al., 2021). For a discussion of genetic heterogeneity of combined oxidative phosphorylation deficiency, see COXPD1 (609060).