Complex II deficiency is a rare cause of mitochondrial respiratory chain defects with a prevalence of 2-23%. It is exclusively nuclear encoded and functions in the citric acid cycle by oxidizing succinate to fumarate and in the mitochondrial electron transport chain (ETC) by transferring electrons to ubiquinone. Of the four subunits, SDHA and SDHB are catalytic and SDHC and SDHD are anchoring. Mutations in SDHA and SDHAF1 (assembly factor) have been found in patients with CII deficiency and a mitochondrial phenotype. We present a patient with CII deficiency with a previously undescribed phenotype of dilated cardiomyopathy, left ventricular noncompaction, failure to thrive, hypotonia, and developmental delay. Also, a comprehensive review of 36 cases published in the literature was undertaken. The results show that CII deficiency has a variable phenotype with no correlation with residual complex activity in muscle although the phenotype and enzyme activities are comparable within a family. For some, the condition was fatal in infancy, others had multisystem involvement and some had onset in adulthood with mild symptoms and normal cognition. Neurological involvement is most commonly observed and brain imaging commonly shows leukoencephalopathy, Leigh syndrome, or cerebellar atrophy. Mutations in SDHAF1 are associated with leukoencephalopathy. Other organ systems like heart, muscle, and eyes are only involved in about 50% of the cases but cardiomyopathy is associated with high mortality and morbidity. In some patients, riboflavin has provided clinical improvement.

INTRODUCTIONSubacute thyroiditis usually presents in adulthood. These cases are usually attributed to viral etiology. The presentation of subacute thyroiditis early in life is very rare. We describe here the youngest child to our knowledge to have Cytomegalovirus (CMV)-induced subacute thyroiditis. PATIENT REPORTA previously healthy I-V12 year-old girl presented with a 2-day history of high fever and upper respiratory tract infection symptoms followed by the appearance of a mildly painful mass in the neck. On physical examination she was highly febrile and irritable, but not sick looking. Neck examination revealed an enlarged, firm left thyroid lobe without fluctuation. There were no palpable lymph nodes and her systemic examination was normal.The child was admitted and investigated for presumed acute suppurative thyroiditis. Laboratory investigations showed normal hemoglobin concentration with normal indices, elevated white cell count (WBC) 19 χ 10 9 /1 (normal 6-17.5), with 68% polymorphonuclear cells (ANC) 13x10 9 /l (normal 1.5-8.5), increased C-reactive protein (CRP) 240 mg/1 (normal 0-8), and erythrocyte sedimentation rate (ESR) 129 mm/h (normal 0-15). Thyroid function studies were normal on day 1: free thyroxine (fT4) 16.1 pmol/1 (normal 5.8-18) and thyroid stimulating hormone (TSH) 2.65 mIU/1 (normal 0.34-5.6); and also normal repeated after 10 weeks during follow up: fT4 11.8 pmol/1, and TSH 4.02 mIU/1. The serum concentration of thyroglobulin (Tg) was markedly elevated," 231 μ^Ι (normal 0-43). Thyroglobulin antibodies were not detected. Ultrasound examination showed a diffuse hypoechogenic enlargement of the left lobe without evidence of abscess formation. The right lobe was of normal size with no change in echogenicity.The presumptive diagnosis was acute suppurative thyroiditis, and an intravenous antibiotic (amoxicillin/calvulanate) was started. Subsequently the child continued to have high fever but remained clinically well, which prompted us to suggest a viral etiology for her illness. Fine needle aspiration cytology (FNAC) and serology for several common viruses (Epstein-Barr, CMV and Herpes simplex) were done. The serum IgM levels against CMV were persistently positive over 10 weeks, and IgG against CMV turned positive, as a confirmatory test. CMV PCR was done and was positive in both plasma and leukocytes. FNAC microbiological studies were negative for Gram stain, and there was no bacterial growth in the culture. The cytology report showed material which almost entirely consisted of blood and numerous degenerating neutrophils and microphages; no malignant cells were seen. Unfortunately, no further viral tissue studies were able to be done on this specimen. The antibiotic was discontinued after 10 days and the patient became afebrile.On follow up after 2 months she remained euthyroid, all inflammatory markers were normalized, and the thyroid gland had returned to normal size. A barium study, done to rule out pyriform sinus or thyroglossal duct, was normal.

Multiple factors control the growth of a child, including genetics, nutrition, and socioeconomic factors. Referral of tallboys who are otherwise well is very rare. However, sometimes, extraordinary tall stature for the age can be a cause of great concern to the parents. We report a case of an Omani child with a de novo mutation of NSD1 that led to his overgrowth and diagnosis of Sotos syndrome (SoS). This syndrome is a rare genetic disorder. Only two cases of genetically proven diagnosis were reported from the Middle East and North Africa region. Therefore, we describe a case and highlight the comorbidities associated with this condition, encouraging colleagues from the region to report their cases to understand better the phenotype–genotype and the natural history of this disorder in this part of the world.