Heterozygous ACAN mutations result in a phenotypic spectrum ranging from mild and proportionate short stature to a mild skeletal dysplasia with disproportionate short stature and brachydactyly. Many affected individuals developed early-onset osteoarthritis and degenerative disc disease, suggesting dysfunction of the articular cartilage and intervertebral disc cartilage. Additional studies are needed to determine the optimal treatment strategy for these patients.

Cystic fibrosis birth prevalence in southeastern Mexico is 1:13,724 newborns. Immunoreactive trypsinogen blood concentration is influenced by gestational age and by the time of sampling. The spectrum of CFTR gene variants in Yucatan is heterogeneous.

Niña de 14 años que acudió a nuestro Instituto al año de vida por prolapso de pólipo rectal con evacuaciones sanguinolentas.  Segunda gesta de una pareja de padre sano y madre afectada con el síndrome de Peutz-Jeghers, al igual que otros familiares por la rama materna.  Existe antecedente de aborto en la madre y tiene una hermana menor aparentemente sana.  La madre presentó amenaza de parto pretérmino en el séptimo mes que se controló con reposo y medicamentos no especificados.  La paciente nació por cesárea a las 41 semanas de edad gestacional, por falta de trabajo de parto.  Presentó llanto y respiración espontáneos, APGAR de 8-9, peso  3.800 Kg, talla  51 cm.  Fue dada de alta como binomio sano a las 78 horas.  El periodo postnatal curso sin complicaciones y su desarrollo neurológico fue normal.

Several patients with the Silver-Russell syndrome (SRS) attending our Genetics Clinic were diagnosed as having persistent metabolic acidosis. Since this abnormality has not been reported previously in the SRS, we reexamined 33 SRS patients to evaluate the frequency and type of metabolic acidosis, the clinical and laboratory findings, and the growth pattern in SRS patients with and without metabolic acidosis. Among them, 14 had a consistent decrease in HCO3- levels. Renal studies in acidotic patients showed urine pH of 5.8 and 24 h urine calcium of < 2.4 mg/kg/24 h; serum creatinine, excretion of glucose, and amino acids were normal, as were renal ultrasound and excretory urography findings. These data supported the diagnosis of renal tubular acidosis, probably type II; the patients were treated with oral bicarbonate and acidosis was corrected successfully. Clinical manifestations were similar in acidotic and non-acidotic patients. The nutritional indices at diagnosis and at last evaluation (at least 8 months after diagnosis) were abnormally low in all patients; however, acidotic patients, treated with bicarbonate, showed an improvement of nutritional status particularly in the weight/height index, although the difference between groups after follow-up did not reach statistical significance. We suggest that metabolic acidosis due to renal tubular acidosis, probably type II, may occur in children with the SRS and should be looked for and treated in all patients.