Amir Babiker

A multicenter clinical exome study in unselected cohorts from a consanguineous population of Saudi Arabia demonstrated a high diagnostic yield

Abstract Purpose Whole-exome sequencing (WES) can help identify known and novel pathogenic molecular aberrations. Here, we examined the diagnostic yield of WES in population from consanguineous unions. Methods We preformed retrospective review of multicenter WES results of an unselected cohort of patients with a wide range of phenotypes. Clinical data and WES reports of 454 patients from 5 centers across Saudi Arabia were analyzed. Testing was performed in accredited commercial laboratories, and all the WES laboratory reports were reviewed again using additional clinical information available to the treating physicians. Results Among the 454 probands, we identified highly likely disease-causing variants in 222, thereby achieving a 49% molecular diagnostic yield. The diagnostic yield was 53% in consanguineous unions and 39% in non-consanguineous unions. About 66% of the identified variants in consanguineous families were homozygous, with an autosomal recessive mode of inheritance. Additional clinical data reclassified 11 positive reported results into 4 inconclusive and 7 negative results, and 22 inconclusive results into 17 positive and 5 negative results. Conclusions The diagnostic yield from WES in our unselected cohort is similar to other studies from the same region, which is a higher yield compared to other international regions largely because of the high rate of consanguinity and partly due to simplified variant interpretation and classification in consanguineous unions.

Tyrosinemia type 1: a rare and forgotten cause of reversible hypertrophic cardiomyopathy in infancy.

BackgroundTyrosinemia type 1 (TT1) is an autosomal recessive disorder caused by deficiency of the enzyme fumarylacetoacetate hydrolase (FAH). TT1 usually presents in infancy with features suggestive of liver disease or with sepsis-like symptoms.Case presentationWe report two Saudi siblings with TT1. Case 1 was a male infant who presented at 2 months old with fever, vomiting and refusal of feeding. Examination revealed a sick-looking infant with signs of severe dehydration and hypovolemic shock. He was jaundiced, and had hepatomegaly and elevated liver enzymes. Echocardiography was performed in light of a lack of response to inotropes, and revealed biventricular and interventricular septal hypertrophies. The ventricular ejection fraction was 65%. Urine organic acid analysis showed elevated succinylacetone, consistent with a diagnosis of TT1. An FAH gene study identified a c.1 A > G homozygous mutation. This patient responded well to intensive cardiorespiratory therapy, tyrosine-free formula, and oral 2-nitro-4- trifluoromethylbenzyl 1, 3 cyclohexanedione (NTBC). Echocardiographic findings reverted to normal after 4 weeks. Case 2 was the younger brother of Case 1, and was born 6 months after his brother had been confirmed with tyrosinemia. Pregnancy and delivery were uneventful. Serum amino acid and organic acid analyses 4 days after birth confirmed tyrosinemia. DNA analysis identified a c.1 A > G homozygous mutation, as in his brother. Echocardiography was normal. Special formula and NTBC were commenced on day 7 of life. The infant remained asymptomatic after 9 months of follow-up.ConclusionsThese cases highlight TT1 as a treatable cause of cardiomyopathy in children. It also supports the idea that early diagnosis and treatment may prevent the development of cardiomyopathy associated with tyrosinemia.

Managing traumatic brain injury in children: When do we need a computed tomography of the head?

• Born in 1948 in Koka Al Mahas near Delgo in Nothern Province, Sudan (Figure 1A). • Elementary and Intermediate schooling in Northern Province. • Secondary school: Port Sudan Secondary School (Figure 1B). • Medical education: Faculty of Medicine, University of Khartoum [1]. • Internship (House Officer): Khartoum Teaching Hospital. • Medical Officer: Omdurman Teaching Hospital. • Medical Officer: Maridi Hospital (Currently, South Sudan).

The spectrum of 46XY disorders of sex development in a University centre in Saudi Arabia

Abstract Background: The term disorders of sex development (DSD) includes congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical. The spectrum of the 46XY (DSD) is so broad. In this study, we reviewed the clinical spectrum of a cohort of patients with 46XY DSD in a tertiary institute in the Middle East over two decades. Objective: To define the clinical spectrum of 46XY DSD in a major teaching hospital, Riyadh, Saudi Arabia. Materials and methods: This is a retrospective, case series hospital-based study. The case notes, laboratory investigations, and imaging studies were reviewed for patients with 46XY DSD over a 20 years period (1989–2010) at King Khalid University Hospital, Riyadh, Saudi Arabia. Molecular genetics were not available in all patients. Results: During the period under review; a total of 56 patients were seen with 46XY DSD due to variable etiologies. Androgen insensitivity syndromes (AIS) and 5-α-reductase deficiency were among the commonest (44.6%), with multiple siblings involvement within the family. Of these, 16 patients were showing variable degrees of insensitivity ranging between complete (n=5, 31.2%) and partial (n=11, 68.8%) insensitivity, whereas in nine patients the diagnosis of 5-α-reductase deficiency was entertained based on hormonal studies. Of interest to see was a high number of patients (n=14, 25%) either with a localized congenital anomalies such as the cloacal anomalies or generalized congenital malformations following the pattern of certain syndromes. Conclusion: A wide spectrum of causes were noted. Androgen insensitivity syndrome was the commonest. In Saudi Arabia, where consanguineous mating is high, 5-α-reductase is also a common cause of 46XY DSD.