Endocrine Abstracts

Background: Klinefelter syndrome is the most common sex chromosome abnormality causing primary hypogonadism and affects approximately 1 to 2.5 per 1000 males. However, other rarer sex chromosomal abnormalities have been associated to testicular dysfunction.

Clinical Case: A thirteen-year-old male was referenced to Pediatric consultation due to obesity starting around age four. Perinatal background: maternal gestational diabetes controlled with diet and 10-kilogram weight gain; caesarean delivery at 40 gestational weeks; Apgar score 4/10 (needed oxygen therapy and initial inflations); birth weight 4580 grams (+2.27 ZS); hypoglycemia neonatal episode. Breastfeeding up to 2.5 years. Clinic background: Some symptomatic episodes of fasting and postprandial hypoglycemia, ENT surgery at 7 years old due to conductive hearing loss and learning difficulties, attention deficit, progressive social problems and opposition behavior, culminating in sexual disinhibition and substance abuse. He was medicated with metilphenidate and topiramate. Family history: maternal obesity submitted to bariatric surgery and father with arterial hypertension and dyslipidemia.Several eating errors were evident. He used to play hockey three times a week. Daily screen time was less than 1 hour. At physical examination, weight: 117.6 kg, height: 182 cm (+3.18 ZS), Body Mass Index: 35.5 kg/m² (+3.48 ZS), blood pressure: 136/58 mmHg (P90/<P5), heart rate: 76 bpm; prognathism and bilateral eyelid ptosis, cervical and axillary acanthosis nigricans, abdominal stretch marks; normal male external genitalia; testicular volume: 12 mL (right) and 15 mL (left); Tanner pubertal stage: G3P5. Complementary investigation: normal lipidogram; glycated hemoglobin: 5.0%; insulin: 16.3 mUI/mL (<30); FSH: 21.4 mUI/mL (0.4-8.7), LH: 8.6 mUI/mL (0.5-5.3), total testosterone: 335.2 ng/dL (15-500), cortisol: 13.9 ug/dL (<23) and normal thyroid function. Normal abdominal and testicular ultrasounds. Chromosome microarray identified a structural rearrangement in Y chromosome and karyotype evidenced a dicentric Y chromosome with impact on spermatogenesis (46X,Yidic(Y)(q11.2)). Whole Exome Sequencing was inconclusive.

Conclusion: This clinical case discloses the importance of carefully integrating all background information with clinical evolution. Furthermore, it highlights the role of genetics not only for sex chromosome abnormalities identification, but also for a better understanding of the patient’s syndromic presentation, as well as management of future prevention.