Clinical Description
To date, 54 individuals with MYRF-related cardiac urogenital syndrome (MYRF-CUGS) (more than 20 unpublished, and 32 published plus an extremely large multiplex family) have been identified with a pathogenic variant in MYRF [Authors, personal observation; Chitayat et al 2018; Pinz et al 2018; Qi et al 2018; Garnai et al 2019; Guo et al 2019; Hamanaka et al 2019; Rossetti et al 2019; Siggs et al 2019; Xiao et al 2019; Globa et al 2022; Gupta et al 2022]. The following description of the phenotypic features associated with MYRF-CUGS is based on these reports.
Variations in genitalia may be the only finding in an individual with MYRF-CUGS and manifestations may be subtle.
46,XY individuals. The majority of reported individuals have a 46,XY karyotype. The genitourinary anomalies are very broad and range from isolated unilateral cryptorchidism to typically appearing female genitalia. Common physical findings may include micropenis, hypospadias, chordee, small testes, bifid scrotum, and/or persistent urachus. Müllerian structures including uterus and vagina (typically hypoplastic) may be present. Consistent with the full spectrum of nonbinary (ambiguous) genitalia, some individuals have varying degrees of testicular dysgenesis including Sertoli and/or Leydig cell hyperplasia, paucity of germ cells, tubular atrophy, and decreased fertility / infertility [
Hamanaka et al 2019,
Globa et al 2022,
Gupta et al 2022].
XX individuals. Only six affected individuals have been reported with a 46,XX chromosomal complement. Of these, three had atypical internal genitalia, including absent uterus, fallopian tubes, small or absent ovaries, absent vagina, or blind-ending vagina.
Ophthalmic involvement. Of 19 individuals with well described and deeply evaluated eye morphology, 16 had high hyperopia (farsightedness). Some were evaluated because of clinical concerns, and some were seen because of their MYRF-CUGS diagnosis. Some were ascertained from cohorts of individuals with nanopthalmos, so this particular finding may be an overestimate. These 19 individuals do not include the family reported by Garnai et al [2019], nor do they include an additional large multiplex family that had ocular phenotyping only, as these individuals may have the ocular-limited allelic condition (see Genetically Related Disorders). Overall, nanopthalmos / high hyperopia appears to be one of the most common features of MYRF-CUGS (see Genotype-Phenotype Correlations).
Nanophthalmos is associated with secondary complications including amblyopia, esotropia, angle closure glaucoma, and spontaneous and postsurgical choroidal effusions [Carricondo et al 2018]. Peripheral chorioretinal scarring and mild retinal pigment epithelial mottling have been reported in some affected individuals and may represent a primary finding in individuals with MYRF-CUGS as opposed to sequela of nanophthalmos [Garnai et al 2019, Hagedorn et al 2020].
Developmental delay (DD) and intellectual disability (ID). There is a broad range of DD/ID from typical development and cognition to severe developmental delay and intellectual disability. Severity and rates of intellectual disability or delayed developmental milestones may be affected by cardiopulmonary defects. Of the 15 individuals who had DD/ID:
Three had speech delay;
Eight had global delays or severe delay (7 of the 8 had cardiopulmonary issues that required extensive hospitalizations and surgeries);
Of individuals without cardiopulmonary malformations, only one was reported with a developmental disorder, in this case autism spectrum disorder.
Cardiovascular anomalies. The spectrum of cardiovascular anomalies is broad, ranging from isolated dextrocardia to hypoplastic left heart syndrome. Scimitar syndrome (see Suggestive Findings) is also commonly reported. Other congenital heart defects that have been reported:
Atrial septal defect
Ventriculoseptal defect
Aortic arch hypoplasia
Coarctation of the aorta
Bicuspid aortic valve
Aortic atresia
Mitral valve atresia
Tetralogy of Fallot
Pulmonary abnormalities and diaphragmatic issues. Of deeply phenotyped individuals, approximately half have either congenital diaphragmatic hernia (CDH) or pulmonary hypoplasia without CDH. CDH can be left-sided or right-sided, with left-sided predominance. Diaphragmatic eventration has also been reported.
Gastrointestinal issues. Although not a prominent feature, three individuals have been reported with intestinal malrotation [Chitayat et al 2018; Authors, personal observation].
There are further reports of affected individuals having gastroesophagal reflux disease, poor feeding, and G-tube dependence, although some of these issues may be secondary to cardiopulmonary disease.
There has also been one report of a 46,XY individual with hepatotesticular fusion and splenotesticular fusion [
Chitayat et al 2018] and one individual with appendiculo-umbilical fistula [Author, personal observation].
Growth/feeding
One individual is reported to have short stature [
Qi et al 2018]; intrauterine growth restriction was found in another individual [Authors, personal observation].
Microcephaly has been observed in three affected individuals [Authors, personal observation].
Poor feeding, which may be secondary to neurologic issues and the effects of severe cardiopulmonary disease, has also been reported.
Dysmorphology. The majority of reported individuals who were evaluated have no recognizable dysmorphic features. Widely spaced eyes have been observed in three affected individuals [Chitayat et al 2018; Author, personal observation].
Other rarely reported features. The following have been reported in a few known affected individuals to date. It is unclear if these findings are rare features of MYRF-CUGS or rare co-occurrences of two unrelated findings.
Neurologic findings
Hypotonia has been reported in three affected individuals.
One individual with an autism spectrum disorder diagnosis has been reported; this individual had no major cardiopulmonary disease.
Two affected individuals had delayed myelination patterns noted on brain MRI.
Endocrinologic. One affected individual had thymic fibrosis and involution [
Pinz et al 2018], and another had hypothyroidism [Authors, personal observation].
Renal. One affected individual with a horseshoe kidney with associated hydronephrosis has been reported [
Rossetti et al 2019].