Phenotypic and cytogenetic variability of patau syndrome in Morocco.

The objective of this work was to identify phenotypic features and cytogenetic aspects of trisomy 13 in Moroccan population. The retrospective study was conducted on a group of 9 cases diagnosed cytogenetically with trisomy 13. The study of sex ratio showed a slight female dominance in our group of cases. The major clinical findings included: Holoprosencephaly, microphthalmia and anophthalmia, coloboma of iris, cleft lip and palate, nasal and ear abnormalities, retrognathism and sloping forehead, polydactyly, capillary hemangiomas, omphalocele, congenital heart defect, renal abnormalities, cryptorchidism, language delay. The cytogenetic study showed the dominance of the free and homogeneous trisomy 13 (56%). Patients who have this formula are dead at an early age (does not exceed one month). However, each of the chromosomal formula, trisomy 13 by translocation and partial trisomy 13 t (13;18), was found in 20% of our patients. The partial trisomy 13 t (13;18) is the only variant that is still alive and the patients with this anomaly suffer mainly from renal and cardiac anomalies with slight dysmorphia and psychomotor retardation. Our study shows the interest of the cytogenetic analysis in the diagnosis accuracy and in the genetic counseling of patients with Patau syndrome and their parents.

Usefulness of urinary glycosaminoglycans assay for a mucopolysaccharidosis-specific screening.

BACKGROUND: Mucopolysaccharidoses (MPS), a group of inherited metabolic disorders characterized by the accumulation of glycosaminoglycans, can be diagnosed early through newborn screening programs. Establishing newborn screening in Morocco is a challenging task for multiple economic and social reasons. Screening in a Moroccan population using 1,9-dimethylmethylene blue urinary glycosaminoglycan (GAG) assays may allow for an earlier diagnosis of MPS. We studied the feasibility of implementing screening in Moroccan children as an alternative to national newborn screening. We determined the reference ranges for GAGs in the Moroccan population, their stability during transport, the effectiveness of this test as a screening procedure for MPS in patients, and its use as a screening test for MPS in the Imssouane region, where the rate of consanguineous marriage is 38%. METHODS: Using dimethylmethylene blue assays, urine samples of 47 MPS patients were analyzed, together with urine samples from healthy controls (n = 368, age ranging from 1 month to 25 years), and from Imssouane region children (n = 350, age ranging from 6 months to 24 month). Precision, linearity, recovery, limits, and stability were tested. RESULTS: Urinary GAGs reference values are age and ethnicity dependent. The validation parameters established displayed great precision and accuracy leading to recoveries according to internationally accepted values for bioanalytical methods. Urinary GAGs were stable for a maximum of 7 weeks at 40 °C. Screening of Imssouane children resulted in the detection of a 6-month-old child, diagnosed with MPS I. CONCLUSIONS: Our results demonstrate the usefulness of quantifying glycosaminoglycans for early screening of MPS.