Endocrine Abstracts

JOINT715

Lujan-Fryns Syndrome (LFS) is a rare neuro-rheumatological X-linked disorders with mild-moderate mental retardation, psychiatric disorders, marfanoid habitus, hypotonia, tall stature, craniofacial dysmorphism, hypernasal speech, normal sexual development and testis size.

Clinical case: Due to the finding of macrocrania, craniofacial dysmorphisms, normal stature growth, and mild learning and speech disorders an 8-year-old boy came to genetic counselling where a diagnosis of Lujan-Fryns syndrome with normal karyotype (46 XY) and exclusion of X-fragile syndrome in patient with pachydermioperiostosis and Raynaud’s syndrome was made. At 21 years of age, she was also diagnosed with hypothyroidism from Hashimoto’s thyroiditis (maternal family of thyroidopathy) and for which she is on L-Tyroxine therapy (with fluctuating dosage). Over the years, the patient has been followed for LFS by Geneticists and Endocrinologists with reported normal stature and pubertal growth and bone maturation, thyroid ultrasound picture compatible with autoimmune thyroiditis, testicular ultrasound in the normal range, brain and pituitary MRI also normal. as well as serum levels of prolactin, GH and IGF-I In March 2024, at the age of 33 years old, the patient was admitted to our department for the first time for group B Salmonella gastroenteritis. GH (0.61 ng/ml- reference limit (RF) 0.00-5.00), IGF-I (84 mg/dl -RF. 82-244), 8 o’clock Cortisol (15.8 mg/dl-RF 6.0-18.4), 8 o’clock ACTH (10.2 pg/ml-RF 0. 0-46); LH (0.3 mUI/ml-RF 1.3-8.6), total testosterone (1.15 ng/ml-RF 2.2-10.5), FSH (0.8 mUI/L-RF 12.4) were below normal and substantially confirmed 6 months later (LH 3.1 mUI/l, FSH 1.0 mUI/L), with normal serum levels of total and free testosterone (2.4 ng/ml -RF 2.2-10.5 and 7.6 pg/ml-RF 1.8-21.4, respectively). An LH-RH test (100 mg ev) was then performed, which revealed a normal LH response (baseline: 5.0 mUI/l, peak at 30’: 17.7 mUI/l)and isolated FSH deficiency (baseline: 1.3 mUI/l, peak at 90’: 2.2 mUI/L). Inhibin B assay was then performed, which was found to be normal (304.4 ng/L-RF 10-357). A spermiogram was not performed due to lack of parental consent.

Conclusions: 1) to our knowledge this is the first described case of isolated FSH deficiency in LFS; 2) even with normal pubertal development and normal testicular volume in LFS it is useful in follow-up to evaluate the pituitary-gonadal axis.