medwireNews: Researchers report the prevalence and characteristics of girls with 46,XY disorders of sexual development (DSD) born in Denmark since 1934.

They found a substantial increase in diagnoses among patients born from 1951 onwards, due to the availability of karyotyping from 1960, and a decrease among births from 2001, which the team attributes to the presence of as-yet undiagnosed cases.

“Thus, we consider the prevalence of 46,XY females to be best reflected by the estimated prevalence in the birth cohort during 1951–2000”, write Agnethe Berglund (Aarhus University Hospital, Denmark) and study co-authors in The Journal of Clinical Endocrinology & Metabolism.

They estimate a prevalence of 6.4 per 100,000 live-born females, although they note that this is a conservative estimate, given that the diagnoses of 23 patients could not be verified. The 124 verified patients included 78 with androgen insensitivity syndrome (AIS), 25 with gonadal dysgenesis, 15 with unknown subtypes and another six with conditions such as StAR mutation and Frasier syndrome.

The researchers note the “common belief” that most 46,XY DSD patients are diagnosed during puberty, which was indeed the case for those with gonadal dysgenesis, who were diagnosed at a median age of 17.0 years. The majority (68%) of these patients were diagnosed during investigations for amenorrhoea.

Amenorrhoea was also a common presenting symptom in patients with AIS, at 28%, but so was inguinal hernia, at 34%, and clitoral hypertrophy, at 15%, while 16% of patients had a family history of AIS. As a result, these patients were often diagnosed in childhood, at a median age of 7.5 years.

Most patients had normal external female appearance (Prader stage 0). Only three patients with gonadal dysgenesis had evidence of virilisation, ie, a higher Prader stage (1–2), whereas 15% of those with AIS were Prader stage 1 and 12% were stage 2–3.

The researchers note that they had anticipated a reduction in diagnostic delay during the study period, “due to increased vigilance among clinicians and due to better diagnostic tools”, but none occurred.

“This indicates that the diagnosis of 46,XY DSD is difficult in many cases, and a substantial decrease in diagnostic delay will only be possible with neonatal screening, which is not realistic from a cost-benefit perspective”, they conclude.

By Eleanor McDermid

J Clin Endocrinol Metab 2016; Advance online publication

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