ATYPICAL GENITALIA IN SILVER-RUSSELL SYNDROME

Abstract

INTRODUCTION
Silver-Russell Syndrome (SRS) is a clinically heterogeneous disorder which is often associated with growth restriction. Genital abnormalities can be present but are not part of the diagnostic criteria. We describe one case of Silver-Russell Syndrome with atypical genitalia.

CASE
A 4-month-old male was referred to our clinic for atypical genitalia. He was born premature at 36 weeks 1 day, small for gestational age (SGA) with birth weight of 1.34 kg (<3rd centile), length of 41 cm (<3rd centile) and relative macrocephaly with head circumference of 32 cm (50th centile).

On further examination, he had dysmorphic features with prominent forehead, frontal bossing and triangular facies. His limbs were asymmetrical with hemihypertrophy of the left upper and lower limbs and bilateral 5th finger clinodactyly.

Examination of the genitalia revealed underdeveloped scrotum with no scrotal fusion, micropenis with stretched penile-length 0.5 cm (<10th percentile), penoscrotal hypospadias and non-palpable gonads. The EMS score was 0, in support of undervirilization.

Investigations revealed intact mini puberty with LH, FSH and testosterone of 1.6 U/L, 14.4 U/L and 2.95 nmol/L, respectively. Other anterior pituitary hormones were normal and 17-OHP was not elevated. Karyotype was normal with 46,XY. Short beta-hCG stimulation test revealed good testosterone level, with normal testosterone to androstenedione (T:A) ratio and testosterone to dihydrotestosterone (T:DHT) ratio, excluding both 17-hydroxysteroid deficiency and 5-alpha reductase deficiency respectively.

He was assessed by the genetic team and was noted to fulfill all the six NH-CSS criteria for clinical diagnosis of Silver-Russell syndrome. SRS methylation testing was sent to determine the molecular mechanism for future recurrence risk counselling.

CONCLUSION
Although SRS is primarily a growth disorder, it may present with atypical genitalia along with growth failure and dysmorphic features. Hence, it should be considered in the differential diagnosis of a newborn with dysmorphic features, SGA and atypical genitalia.