46,XY difference of sex development due to isolated 17,20-lyase deficiency

What it is

A rare difference of sex development due to reduced 17,20-lyase activity that affects individuals with 46,XY karyotype and is characterized by female or atypical external genitalia with reduced phallic size, hypospadias, incomplete fusion of the labioscrotal swellings, cryptorchidism, and a blind vaginal pouch. Blood pressure and electrolytes are normal whilst hormonal investigations show normal basal and stimulated levels of cortisol, and low basal and stimulated androgen levels.

Key facts

Prevalence

<1 / 1 000 000

Age of onset

Neonatal

Inheritance

Autosomal recessive

Classified as

Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

Genes

ICD-10 codes

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Cross-references