Neonatal McCune-Albright syndrome with survival beyond two years

The longest reported survival of a child with McCune-Albright syndrome and a severe early presenting phenotype consisting of neonatal cushing syndrome, cardiac and liver diseases

Neonatal cushing syndrome (NCS) is a rare disease that results from prolonged exposure to high cortisol levels. McCune-Albright syndrome (MAS) is an exceedingly rare genetic disorder characterized by cafe-au-lait skin spots, bone fibrous dysplasia and multiple endocrinopathies. We describe a case of a premature neonate with Intrauterine Growth Retardation who presented with hypercortisolemia, neonatal transaminitis and cardiac dysfunction. Further evaluation revealed significant bilateral adrenal hyperplasia leading to the diagnosis of NCS as part of MAS. Despite maximum medical therapy, including metyrapone, the baby's refractory hypertension, hyperglycemia and persistent failure to thrive (weight of 1.4 kg at corrected age 38 weeks) necessitated bilateral adrenalectomy. This case did not initially demonstrate the classic MAS triad, notably, the absence of skeletal manifestations. There has been no previous description of a baby who has had all the early life-threatening features present and survived beyond 18 months. This case highlights the severity of the phenotype and the challenges involved in diagnosing and treating NCS and MAS in neonates.

Cushing syndrome as a failed cardiac screen in a patient with McCune–Albright syndrome: a case report

Background

McCune–Albright syndrome is a complex disorder encompassing multiple endocrinopathies. These manifestations are secondary to a mutation in the stimulatory G-protein alpha subunit. Cushing syndrome is due to autonomous secretory function of the adrenal gland and is present in 7.1% of patients with McCune–Albright syndrome. Cardiac newborn screenings assist in the identification of critical congenital heart disease. These screenings have become part of routine postnatal care nationwide.

Case report

A 6-week-old Caucasian male presented to a cardiologist at the University of Tennessee Health Science Center with left ventricular hypertrophy and poor feeding after a failed cardiac newborn screen. He had been previously seen at 2 weeks by a cardiologist on follow-up for abnormal critical congenital heart disease screening. Electrocardiogram and echocardiographic studies identified hypertrophic cardiomyopathy. Other examination findings revealed multiple characteristic café-au-lait lesions along with hypotonia and rounded facies. Given his cardiac disease, he was admitted to the hospital, where an evaluation was done for Cushing syndrome, showing elevated cortisol by immunoassay of 38 μg/dL (1.7–14.0 μg/dL, Vitros 5600) after a dexamethasone suppression test and urinary cortisol elevated to 35 μg/dL/24 hours (reference range 3–9 μg/dL/24 hours) (Esoterix; Calabasas, CA). He was started on metyrapone therapy to block synthesis of cortisol. His cortisol improved and was suppressed less than 2 μg/dL. His hypertension and clinical features of Cushing syndrome improved.

Conclusions

This case demonstrates a unique presentation of Cushing syndrome in a young infant. This is the first case to our knowledge showing significant left ventricular hypertrophy resulting from Cushing syndrome identified following a failure on a critical congenital heart disease screen. It highlights the importance of considering of McCune–Albright syndrome in patients with Cushing syndrome, especially if other clinical features are present. Medical therapy can be used to treat Cushing syndrome and can result in improvement in the cardiovascular pathology.

A Novel GNAS Mutation Causing Isolated Infantile Cushing's Syndrome

Infantile Cushing's syndrome is potentially found as part of McCune-Albright syndrome (MAS) which is caused by postzygotic somatic mutations of the GNAS gene. MAS is typically characterized by a triad of polyostotic fibrous dysplasia, café-au-lait skin pigmentation, and precocious puberty or other endocrine hyperfunction. Here, we describe a 2-month-old female infant with features of Cushing's syndrome without café au lait spots, polyostotic fibrous dysplasia, and clinical evidence of other endocrine hyperfunction. Investigations demonstrated adrenocorticotropic hormone-independent Cushing's syndrome with bilateral adrenal gland enlargement. Whole-exome sequencing of leukocytes identified a de novo heterozygous novel missense mutation (c.521G>A, p.Cys174Tyr) in the GNAS gene. The patient experienced clinical improvement of Cushing's syndrome during ketoconazole treatment. Her clinical course was complicated by Pneumocystis jiroveci pneumonia. She also had shortened activated partial thromboplastin time indicating a hypercoagulable state and resulting in pulmonary embolism. She eventually manifested gonadotropin-independent precocious puberty at the age of 13 months after ketoco-nazole was discontinued. This patient demonstrated that Cushing syndrome can be the presenting sign of MAS in infancy. A high index of suspicion followed by genetic analysis is essential in order to establish a diagnosis.

Neonatal McCune-Albright Syndrome: A Unique Syndromic Profile With an Unfavorable Outcome

Somatic gain‐of‐function mutations of GNAS cause a spectrum of clinical phenotypes, ranging from McCune‐Albright syndrome (MAS) to isolated disease of bone, endocrine glands, and more rarely, other organs. In MAS, a syndrome classically characterized by polyostotic fibrous dysplasia (FD), café‐au‐lait (CAL) skin spots, and precocious puberty, the heterogenity of organ involvement, age of onset, and clinical severity of the disease are thought to reflect the variable size and the random distribution of the mutated cell clone arising from the postzygotic mutation. We report a case of neonatal MAS with hypercortisolism and cholestatic hepatobiliary dysfunction in which bone changes indirectly emanating from the disease genotype, and distinct from FD, led to a fatal outcome. Pulmonary embolism of marrow and bone fragments secondary to rib fractures was the immediate cause of death. Ribs, and all other skeletal segments, were free of changes of typical FD and fractures appeared to be the result of a mild‐to‐moderate degree of osteopenia. The mutated allele was abundant in the adrenal glands and liver, but not in skin, muscle, and fractured ribs, where it could only be demonstrated using a much more sensitive PNA hybridization probe‐based FRET (Förster resonance energy transfer) technique. Histologically, bilateral adrenal hyperplasia and cholestatic disease matched the abundant disease genotype in the adrenals and liver. Based on this case and other sporadic reports, it appears that gain‐of‐function mutations of GNAS underlie a unique syndromic profile in neonates characterized by CAL skin spots, hypercortisolism, hyperthyroidism, hepatic and cardiac dysfunction, and an absence (or latency) of FD, often with a lethal outcome. Taken together, our and previous cases highlight the phenotypic severity and the diagnostic and therapeutic challenges of MAS in neonates. Furthermore, our case specifically points out how secondary bone changes, unrelated to the direct impact of the mutation, may contribute to the unfavorable outcome of very early‐onset MAS. © 2018 The Authors JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

The Rare Neurocutaneous Disorders: Update on Clinical, Molecular, and Neuroimaging Features

Phakomatoses, also known as neurocutaneous disorders, comprise a vast number of entities that predominantly affect structures originated from the ectoderm such as the central nervous system and the skin, but also the mesoderm, particularly the vascular system. Extensive literature exists about the most common phakomatoses, namely neurofibromatosis, tuberous sclerosis, von Hippel-Lindau and Sturge-Weber syndrome. However, recent developments in the understanding of the molecular underpinnings of less common phakomatoses have sparked interest in these disorders. In this article, we review the clinical features, current pathogenesis, and modern neuroimaging findings of melanophakomatoses, vascular phakomatoses, and other rare neurocutaneous syndromes that may also include tissue overgrowth or neoplastic predisposition.